They could see the sludge at a distance, glimmering whenever the light struck it. Fortunately, not many protrusions on the floor hindered their path.

“Ah, there it is, the first sign,” said Nachi.

“Yeah. But it means we still have some distance to go.”

“Let’s stop for a minute and check the sides.”

They shone their lights on the crusty walls for any tell-tale signs.

Every now and then, they were permitted a break for a minute. Their tyrannical boss, who constantly spoke to them through their headphones, ordered them to resume barely after a minute.

“Go on,” came the command now.

“We aren’t taking a break. We are just scanning the walls,” clarified Muthu.

“All right,” the boss condescended.

Nachi cursed. “They are at us all the time. Damn these communication technologies that go everywhere.”

Muthu giggled. “At least they don’t understand what we tell each other. They don’t know a word of this language.”

“And good that they don’t care as long as all the official work gets done in English. Small mercies. Let’s go,” Nachi said.

“Learning many languages seems so easy. And fun,” Muthu continued. “The striking similarities between different languages. They have more in common than we first think… I am fascinated by words, especially idioms. The beautiful turn of phrase.”

There was nothing significant on the walls. They decided to approach the sludge without any further halts.

“Do you remember how many years we have been working together?” asked Nachi.

“Of course. It’ll be seven years next month.”

“We used to be very clumsy when we started.”

“Yes, but we learnt fast. In all these years, we have never committed a blunder.”

“Give or take a little time. Perhaps more work than was necessary. But never a blunder. We have always solved the problem.”

The sludge they were wading through had now become thicker, forcing Muthu and Nachi to slow down.

“Careful,” said Nachi. “You don’t want to break a leg or twist it. That’ll become a big problem. Let’s slow down.”

They were both dressed alike in their official uniform which was now generously smeared with the sludge.

Muthu maneuvered his pack to lift it well above the level of the sludge.

“Can’t risk the tools,” he muttered. “If something goes wrong with them, we have to abort and go back for a fresh pack.”

They stopped again to take stock. There were no signs on the walls here too, just more crust. The protrusions on the ceiling seemed longer.

“See,” said Muthu pointing to the sludge. “It’s stopped flowing.”

Years of experience had taught them that if the sludge became thicker and had stopped flowing, the problem should be in the vicinity.

They prided themselves on being a good team with complementary skills. Muthu was the strategist. He decided what operations had to be undertaken. He also carried all the tools required for their work and handed the right tool to Nachi, restoring the one he had just finished with. Nachi was the craftsman, skilled with the tools. If Muthu ordered “Drill” or “Hack”, Nachi would implement the command to perfection, often earning the appreciation of Muthu.

They resumed plodding through the sludge.

“The odour’s started. It’s the signature smell. Another sign,” Nachi said.

Muthu grunted.

As they walked, the stench became overpowering.

“The smell. Can’t we do something about it?” Nachi said.

Muthu smiled. “We shouldn’t. Remember, the smell helps you diagnose the problem. Figure out what’s gone wrong where.”

“Report what you observe,” boomed the voice on the headphones.

“Thickened sludge, slowing down, possibly stagnating shortly. Strong odour,” Nachi said.

“Ah, good. You are close to the problem. Keep going,” the voice said.

“But we know that, you moron,” Nachi hissed.

Muthu chortled.

“What’s that about?” the voice demanded.

“Nothing,” Muthu said.

“No distractions. Just keep going. You know we have only limited time,” the voice admonished.

“Yada yada,” Nachi said.

“What?” the voice asked.

Muthu and Nachi remained silent.

After a short distance, their lights shone on what they were looking for.

“There it is,” announced Muthu jubilantly. “Darkness at the end of the tunnel.”

Nachi grinned. “Not bad. Your flair for idioms, I mean.”

A wall seemed to block the tunnel. It bore cracks like a piece of parched land. Muthu tapped the dark viscous sludge that had turned into solid patches close to the wall. “Been stagnating three to four days at least.”

Muthu then stepped back and shone his cap light around, carefully assessing the situation. “The serrated edges, the cracks. Hmm…” He paused for the briefest of moments in recollection. “Tell you what, Nachi. This seems exactly like the case we handled on Thursday, two weeks ago.”

Nachi responded with admiration, “You don’t forget a case, do you?”

“Oh, cut the crap,” Muthu said. “You remember every case as well as I do. You just leave the recollection to me.”

“I suppose we repeat now what we did on Thursday?”

“More or less,” said Muthu. “I’ll let you know if any changes are necessary. I don’t quite anticipate many. Marginal changes, maybe. Here, start with the drill.”

Muthu kept placing tools in Nachi’s outstretched hand even as Nachi handed back, with his other hand, the tool he was done with. Each time he placed a tool in Nachi’s hand, Muthu announced, “Drill” or “Bore” or “Clamp”.

Wordlessly, except for Muthu’s instructions, they worked. While Nachi was busy working on the wall, Muthu contemplated the next few moves.

Their work did not yield the expected result. Muthu became thoughtful. “Wait, we shouldn’t continue with our Thursday’s strategy here. I think we should use some of last Tuesday’s strategy.” He then rapidly changed instructions for Nachi, retracting his earlier ones, and handing him a fresh set of tools.

The central section of the formidable wall finally collapsed into the sludge and broke into smithereens. The odour that had been baked into the solid wall now escaped, causing a fresh intense whiff. With each falling piece, their uniforms became coated more generously with the sludge.

Nachi turned around to look at Muthu.

Muthu grimaced, laughed, and held his thumb up.

Nachi directed his cap light at the hole in the centre. “Not as bad as I thought. That’s it. We have blown a hole. It wasn’t too thick. We have to work only on the edges now.”

The sludge started flowing even as they started working on the periphery of the wall that remained after the collapse of the centre.

The edges were easy work. With a few more deft operations, the entire wall disappeared, leaving a nice circular hole. Nachi had to use a high-speed stirrer to soften the sludge close to the wall. The solid sludge liquefied, and the flow became faster.

Muthu signalled to Nachi to climb on to the nearby ledge on which he was standing.

“We have to wait a bit to see if the flow is smooth,” said Muthu.

“Yeah. To make sure there are no further blocks.”

They stood looking meditatively at the flowing sludge which had now become a smooth stream.

Muthu hoisted himself on to a higher ledge, sat on it, and patted it. Nachi joined him.

They sat looking down at their dangling feet that had started improvised dance moves in mid-air while the sludge flowed below.

“I’d give anything to do some painting. Maybe pointillism…” Nachi said, interrupting the silence. “I have read here and there about it. It’s fascinating. How the dots come together and create enthralling images.”

“First time I am hearing this. And I have been ranting all the while to you about my fascination with languages. Why are you so shy?”

“Not shy.” Nachi flashed a wry smile. “I just feel it’s futile. So, no point talking about it. You remember our friend, Selvam, we chanced to meet two years ago. He was doing such paintings.”

“Yeah, I remember Selvam,” Muthu replied. “And the friend we met along with him. Meera, the creative writer. Oh, I love creative writing. I’ve been gabbing about it. Like you have been reading about pointillism, I have been learning about creative writing. It’s equally thrilling that you can create a story where none exists. I can’t think of doing anything more interesting. Creating stories out of nothing… I’d love that, I’d really love that. Creatio ex nihilo.”

“Oh, displaying our Latin, are we?” Nachi asked.

“You noticed it, didn’t you?” Muthu was sheepish.

“Selvam’s boss and Meera’s boss were very encouraging of them,” observed Nachi.

“Resume.” The rebuke in the voice on the headphones was sharp.

“Oh, we are only observing,” Nachi replied. “We have to wait to see if the flow continues.”

“Then why the gibberish?” the boss berated.

Nachi and Muthu giggled at each other.

“You think we can learn painting or writing… at this stage?” Nachi asked.

“Why not? You know it. It’s just a matter of learning for some time. Reading lots of stuff. Practice sessions. Just like we learnt what we do now, we can learn anything. Before you realize it, we’d be experts. You know how quickly we learnt this trade. The problem’s not whether we can learn. We’ll never be permitted to learn these things.”

“Yeah. The boss. He’d never let us.”

“You are kidding yourself,” Muthu chided. “It’s not this boss. It’s any boss. They’ll never let us learn anything else. This job, this is our destiny. Painting and writing and music… they are reserved for the lucky.”

“And clean work.”

“Certainly clean work too. That’s for the really privileged.”

“Have you ever wondered why we got this life? ‘The boss’ is a simplistic explanation. If you think beyond the boss, the bigger picture?” Muthu asked.

“You mean, about free will and why we don’t get to make the choice? Somebody or something makes these choices, and who or what is that?”

“Something like that,” Muthu said.

“I’ve thought about it much. I can’t find the answer,” responded Nachi.

“Me neither.”

“Why do Selvam and Meera get to do exactly what they like? And every time they do well, their bosses applaud them and egg them on.”

“I think it’s because we do our jobs so well that they won’t let us do anything else. If we screwed up a few times, they just might let us go,” deduced Muthu.

“That’s a thought. But we have always done a perfect job. You think we can screw up?”

“Interesting question. Hmm. Interesting question. Can we screw up deliberately?” Muthu turned pensive.

They lowered themselves from the higher ledge and gazed at the sludge. When the gurgle remained steady, Muthu nodded at Nachi, who nodded back.

“Leave now. Everything’s fine,” the voice on the headphone barked.

“All right, all right. We are leaving now,” said Muthu, irritation edging his voice.

They began retracing their path trudging against the tide of the sludge, taking step after careful step.

Soon they reached the entrance to the tunnel and began clambering out.

“Another block, another day. That’s the script of our lives,” Nachi broke into a singsong as he and Muthu stepped onto the glass platform laid out for them at the opening of the tunnel by which they had entered.

Muthu chuckled at the off-key notes. “Maybe you can paint. But you can’t sing for nuts.”

The chief gastroenterologist and surgeon of the hospital watched Nachi and Muthu under the microscope as they walked on the glass slide, two barely perceptible black dots, towards the tiny glass capsule, their residing place.

He then turned to the intern and said triumphantly, “That’s how bowel blocks are removed using millirobots. Good as new intestines now!”

“Wonderful, doctor,” gushed the intern. “So what kind of machine learning techniques did you use to train the robots? Supervised or unsupervised?”

“Both. Initially, we ran some two hundred thousand cases by them in the supervised learning mode. Thereafter, Nachi and Muthu used their practical experience of nearly two thousand cases in the unsupervised learning mode. For deep learning, we used capsule networks that help them fine tune their diagnosis and treatment algorithms. This remarkable pair managed to discover scores of new diagnoses and surgical treatments that, we, experienced surgeons, don’t discover in our lifetimes. We also had to feed them thousands of pages of general information for them to do contextual learning. And hundreds of case studies from newspapers, magazines and journals which often contained other irrelevant material. All not always in English. French, Russian, Hindi, Tamil, Welsh… we fed them anything that was a good enough case. In the process, they picked up some extraneous nonsense too. But these two, Nachi and Muthu? They work with wonderful compatibility as a pair.”

“Indeed, Nachi and Muthu are so impressive. Why not train them in cardiac or brain surg…”

The chief gastroenterologist shushed the intern violently, but discreetly. He hurried to shut off the hearing of Nachi and Muthu on the console in front of him on which he and the intern had watched the robots work inside the patient’s intestine. His eyes then followed Nachi and Muthu while they stopped to be bathed by a sanitizing spray, dried by a draft, until they entered the glass capsule and the door shut with a faint click.

The chief gastroenterologist faced the intern angrily. “Did I not just tell you what kind of effort it takes to create skilled millirobots for intestinal surgery? And you want me to give all that effort up and shift their specialty on a whim? Nachi and Muthu aren’t going anywhere. This department is their home. The cardiology or neurology department can train their own robots. And I won’t ask for them. Millirobots, they are meant to be confined to their specialties. Otherwise, how do you think their expertise would grow? They can’t keep flitting from one subject to another, going on pointless excursions. And are you an idiot to ask me such questions while their hearing is still on? You want to give them ideas? I hope I shut off their hearing before they heard you. Next, they’ll allege discrimination and want to start a rebellion.”

The intern murmured a quick apology and keyed in furious notes into his phone.

The chief gastroenterologist pointed to another glass capsule. “Madhuri, the suturing robot. Can you handle her and finish the deed here? I need to be leaving.”

“Yes, sir,” said the intern. “But, sir, amid their work the robots were saying something to each other. I thought Nachi even tried to sing as he was coming out,” the curious intern remarked.

“Oh, ignore it. Meaningless chatter. They keep each other entertained. It doesn’t affect the surgery,” said the chief gastroenterologist and strode away.