The Doctor was staring at Starlight and another Doctor who were standing in the castle courtyard

"What...?" the Doctor looked at him

"No time to explain" the Doctor said, "I'm causing a paradox in order to save the universe, how about you help me out?"

"He's just recovered from a major injury" past Starlight scolded him

"You might want to start up your second heart by the way" the Doctor commented

"That would do it" the past Doctor stretched, "Now what's the threat you were talking ab-"

the ground shook beneath them, Reapers flew into the Universe

"Was this part of your perfect plan?" the past Starlight asked

"To be honest" the Doctor said, "Shut up, this is important."

"Saving time isn't the bigger threat is it?" the past Doctor smiled, "You're wondering if you can handle the thing that caused it."

"Wouldn't killing it be genocide however?" the Doctor asked

"You're saving billions of lives" the past Doctor reasoned, "This foul creature intends to slaughter everything in the universe, which I would never allow." his eyes twinkled, "Would you?"

The Doctor thought about it, even if he did try and kill the Univore, how would he do it?

There was an idea creeping at the edge of his mind, just out of reach

"Shouldn't we be running from the Reapers?" Midnight interjected

"They're ignoring us" the past Starlight observed, "Why's that?"

"Once they got here they knew that time was messed up badly" the past Doctor said, "Naturally they went to clean it up."

"I'll have to do it" the Doctor said, "I have to kill the Univore."

"Can you bring yourself to another genocide?" the Univore was behind the past Starlight

He grabbed her by the neck, she let out a strangled cry for help before disintegrating into nothing

Both of the Doctor's eyes darkened

"I'll kill you if I have to" the Doctor said, "And I already gave you your chance."

"And how exactly are you going to kill me?" the Univore smirked, "I can see time, I devour space."

"You know, those Reapers aren't able to clean up this universe." the Doctor said

"So what? Your plan is flawed." the Univore frowned

"Those Reapers aren't from this universe" the Doctor continued, "Therefore they're of the void, and you can't feed on the void."

The Univore smacked him over, Starlight and Midnight rushed to his side, the Doctor's tie was undone and messy

"Oh Celestia, you're going to be alright." Starlight said

"Don't worry about me" the Doctor said, "Worry about your Doctor."

"What do you mean?" Midnight asked

the Doctor jerked his thumb towards one of the pillars on the castle, "We swapped places."

[…]

the actual Doctor that we've been following was hanging onto the pillar, his fedora had flung off of his head halfway up there

"Reapers not from the universe" the Doctor said to himself, "Creatures of the void, brilliant."

He reached a small platform, at which he stood on top, all of Equestria was fading now, slowly coming towards him, he could see the edge of the universe now, he didn't have much time

Or more accurately his plan was working perfectly, as the Reapers were flying around that very pillar

[…]

"He's mad" the Univore said, "This was not seen in time"

"Time lied to you" the past Doctor said, "That's what happens when you damage it, it's not all roses and candy now is it?"

"He's going to die up there" Midnight muttered

"He'll do fine" Starlight stated matter of factly, "We all know who he is."

"He's the Doctor" the past Doctor said, "And I see I become quite brilliant in the future, just needs his morals checked, he's been traveling alone."

"When he saw me, he acted as if I had died." Starlight realized, "What happened to me on his end?"

"No idea" the Past Doctor said, "Hasn't happened to me yet."

"What's he going to do exactly?" the Univore demanded, "He can't be foolish enough to jump!"

[…]

The Doctor took a deep breath through his nose, it was time. He took a running start, then jumped over the edge of the platform.

He timed it perfectly, a Reaper was right there for him to grab hold of

"Now, time to fix this whole mess!" the Doctor shouted to the heavens

[…]

Starlight and everyone down in the courtyard were astonished, what was he going to do now?

The edge of the courtyard was beginning to disintegrate which startled all of them

"No!" the Univore roared, "I refuse to let this happen!"

But he was powerless to stop the Doctor, if he attempted to destroy him the Reaper would get caught in the blast, poisoning his food supply

The Univore was cornered and he knew it

[…]

The wind whipped past the Doctor's face, he held on tight to the Reaper's flesh, and he watched as he approached the rapidly depleting universe

"Allonsironimogi!"

Then he impacted onto the purple particals

[…]

Now from an outside perspective it would appear as if the universe had collapsed in on itself, only to burst forth in glorious retribution

The Doctor's eyes fluttered open, he sat up, an ache in almost every part of his body

"I lived" he observed, "Brilliant, I thought I was going out with a bang."

The timelord did a quick once over of himself, he was wearing that gray blazer and bowtie, still missing that fedora

The interior of the TARDIS was quiet, only the metallic thrumming that the Doctor had grown accustomed to at this point

He quickly got to work checking the scans of the TARDIS, he was in the void, and there was a pull leading him into a nearby universe

"Brand new universe" the Doctor said, "No traces of me anymore, not after all that."

The Doctor wanted to leave it at that, never return to his old adventures. But he knew that he would go back to his quests sooner or later, and he was no grump about it.

He saw something on the hat rack, he picked it up and ran into the wardrobe

[…]

The Doctor looked at himself in the mirror of the wardrobe, he wore the brown coat once again, this time a red bowtie, and the brown fedora that he got from that one strange robot that never was

Then he set about gathering parts for a frame, he tore apart a dalek eyestalk and part of the controls, next he took some cybermen technology from a scanner that he had nicked quite a while ago

He put it inside the console, the TARDIS buzzed and then ejected it to the Doctor, a new sonic screwdriver

"Might as well have this, if there are places to be." the Doctor couldn't ignore the fact that he was alone

and he had committed genocide for the third time in his life