The Doctor awoke in a dark room, containing nothing but a small window, blocked by large, metal bars. Through his confused and dizzy state, he tried to get up from his uncomfortable kneeling position on the floor, only to realize that his hands were tied firmly behind his back. Realizing that the situation was graver than he had first presumed, the Doctor scanned his surroundings. He was entirely alone, his tweed jacket was missing, his throat was entirely dry, and his head pounded in the same way it had when Amelia had smacked him with a cricket bat. His hands were tied with rope, which he was thankful for, because he had all too much experience with handcuffs and knew how much your wrists hurt once they were removed. Just as the Doctor attempted to stand up without the use of his arms for a second time, the large, metal door to his right slowly opened with a heavy, hollow sound.
A thin, suited figure strutted inside, closing the door behind him with a kick of his dress-shoed foot. The Doctor saw the man's tousled blonde hair, but couldn't bring himself to make the conjecture that he desperately hoped was incorrect.
"Hello there, Doctor," the Master grinned, stalking forward until he was right above the struggling Doctor, gazing down upon him. "You've been here quite a while, if you weren't able to tell. Thirsty, I presume?" He squatted down until his face was inches away from the Doctor's. "Parched?" The Master whispered tauntingly, turning his head on an angle that allowed him to view his Doctor's new appearance.
"How are you-" the Doctor began; only to be cut off be the Master's slender finger against his lips.
"Now is not a time for questions," the Master said, allowing the heat of his breath to reach the Doctor's skin. He stood up and began pacing around the Doctor, pausing only occasionally to look at his prisoner dramatically. "Now is a time for answers. And I believe, unless you are far less intelligent than I thought, you remember the question I just asked."
Reluctantly, the Doctor responded. "Yes, of course, I've been here God knows how long, but since when are you one to treat your guests hospitably?"
The Master chuckled and began rummaging around in his pocket, eventually pulling out a flask. He unplugged the stopper and threw the container at the Doctor's knees, allowing it to begin pooling over the floor. The Doctor looked up at his Master hesitantly, questioningly. "Well? Drink up."
The Doctor stared at the growing puddle on the floor before tentatively leaning down to slurp up some of what he hoped was water. After realizing that, indeed, it was only water, the Doctor abandoned his previous fears of what the Master was up to and began lapping up the water as fast as he could.
The Master soon grew impatient and grabbed a handful of the Doctor's hair, alongside the flask, and pulled him upright again. "How can you expect me to wait this long?" He removed a pocketknife from the same pocket as the flask and brought it behind the Doctor, to free him of his bonds. "Here. Finish this." The Master said, thrusting the still-full flask into the other Time Lord's reddened hands. The Doctor brought the flask to his lips and began to chug- never had he thought he could have loved water this much. It was so incredibly refreshing. It certainly was taken for granted. He would have to take advantage of water more often. Perhaps he would take Rory and Amy to a water-based planet once he returned to…
A thought struck him. What if he never returned to the TARDIS? What if the Master never released him? He was about to open his mouth to ask what his fate would be, when he realized he was still drinking fresh, cool water from the flask. No way could such a small container hold any more than a few cups of water. The Master clearly saw the confusion in the Doctor's expression, and leaned down, eye-to-eye with the Doctor once again. He leaned into the Doctor's ear and whispered, "Bigger on the inside." The Doctor continued to drink the flask's sweet water until it became a burden. However, the second he lifted his lips from the container's opening, the Master came swooping in with a new threat or challenge. It lasted this way for what felt like hours, until finally the last few drops of liquid had been consumed from the flask. "What do we say?"
"Thank…you…" the Doctor responded begrudgingly between pants. He had gone without sufficient oxygen for far too long, and was just now catching up with himself.
"Now, what else do people need to survive?" The Master asked rhetorically, feigning confusion. "Hmm… Food, water, shelter… Tell me, Doctor, might you need to use the toilet?" The Doctor was instantly aware of the pressure that was building in his lower abdomen. He nodded frantically. "Oh, no worries- the door will be unlocked in just a bit." The Master responded teasingly. The Doctor, however, was not relieved. Clutching his abdomen, he slowly made his way to his feet and began stumbling towards the door that the Master entered through. "Not so fast- I just told you. That door is locked, and I will unlock it when I deem it fit."
"Please." The Doctor begged. "Please- I desperately need- I need to-"
"Desperately need to what?" the Master interrupted. "Need to piss?" The Master smirked as the Doctor cringed in response to such a humiliating notion. He continued, fake sincerity dripping off of his words. "Oh, Doctor, only children piss their trousers. I'd hate to see you reduced to nothing more than- than a baby. Quite embarrassing, that. Couldn't you just wait a bit longer? I'm sure you could hold it."
The Doctor had contorted himself into a position that made his predicament the most tolerable. He was scared to answer, scared to make any sudden movements that could increase pressure on his bladder. The Master, grinning somewhat creepily, stalked towards him. The Doctor assumed he was going to stand in front of him and attempt to humiliate him further, but instead the Master stepped behind the Doctor, placing his hands over the hands of the other Time Lord. "Let me help you out there…" the Master leered. He began to press onto the Doctor's lower abdomen, causing the Doctor to scream in pain.
"STOP! NO!" the Doctor screeched, uselessly attempting to get the Master away from him without moving his general position. The Master began lessening the pressure. "Please, I'm- I'm going to go." the Doctor warned, near tears.
"Oh, please don't. You know only babies piss their pants, Doctor. Are you a baby? Just wait a bit longer, that's all! What kind of person doesn't have the basic self-control to decide when they're going to piss?" the Master chided, eyes never leaving the Doctor, so that he would never miss one of his gloriously humiliated responses.
"You-YOU did this to me!" the Doctor cried.
"Oh, did I?" the Master responded, grinning cheekily.
"I- I can't. I'm- I'm-" the Doctor began.
"Please, don't, Doctor. Here, I've got you…" the Master grabbed the Doctor and began lying him down in the center of the cell, in the process placing the slightest bit of pressure on the younger-looking Time Lord's bladder.
"NO! NO I-" the Doctor screamed, all too late. The Master stood above him, watching the dark spot on the Doctor's trousers expanded and begin to form a puddle on the cell's floor.
"Oh, dear. I suppose I thought too highly of you, Doctor. If you don't mind, I'm going to excuse myself. You see, I can't stand the smell of piss, and I think that's what this room will be smelling of for quite a while. I'll send your humans in for you in a bit." the Master sneered before exiting the cell with a skip in his step.
Later, Amy and Rory entered the Doctor's cell to find their infallible time traveler sprawled on the floor- piss flooding his trousers, tears staining his cheeks, and a sob caught in his throat.