He hears that vindication can be rather sweet. This mass murderer, this slimeball of a man who kills for pleasure with a smarmy, cat-ate-the-canary grin; they all say he won't kill again. He's changed or he's 'not that bad' or something.
The Doctor has seen men like him before. He's seen so many die because of that. Because someone thought giving them a chance was worth it.
I'm not here to kill him.
He tells them all he needs to be stopped. Gives him one chance and one chance only. It's worth it to give him this once chance, because it just makes proving them wrong and himself right worth it. Isn't it worth it?
If I told you the truth, your hearts would break.
He kills again.
And the Doctor feels no sweetness, no light, not anything but failure. He thinks he can save him. He wants to believe he can save him.
He tries for revenge next. (Someone once told him that revenge was best served hot.) Packs the man up in the TARDIS, and sets four courses, ending in Volag-Noc, the stronghold of a prison he spent three years trapped in when Martha was captured.
It's a game. A mind game. A mind game that will end in the mass murderer being captured and put where he belongs. He's planned this sort of thing before, but it couldn't be executed.
You mean you're just going to…keep me?
He shakes off old memories and stands against his console, looking his fiercest. The murderer springs the trap, follows all the little mind games perfectly, like he was reading aloud from a script.
The revenge is supposed to be sweet. Cold but sweet. They stop off at Tabula Rasa, and he swears he can see change in the young murderer's eyes. He can see that he's coming around. He wants to see that he's coming around.
Please, we're the only two left, there's no one else…Regenerate!
How about that? I win.
His hand wavers over the control to Volag-Noc, and he sets the destination elsewhere. He thinks he can save him. He has to save him.
There isn't relief.
Their relationship now is strained at best, positively brutal at worst. He can't decide if he pities him, hates him, cares for him, or despises him. They walk a thin line, and he can't seem to fall onto a specific side. A drop of water sliding along a thread. He figures that once he finds a side, things will be easier.
The pressure will release like a pin to a blister.
It's time to change. Maybe I've been wandering for too long. Now I've got someone to care for.
There's never change. The vindication tastes raw and someone always gets hurt. Revenge is a dish too cold for the Doctor, better feasted on by men who would sooner die than regenerate and have an old rival "win".
He has to just be a man. No gimmicks, no motives. Just a man. If he isn't, he can't save him. If he can't save him, then he risks losing this murderer the way of the last one he placed in his care.
And maybe, just maybe, if he saves him, then he'll find relief.
Muse: The Doctor (Ten)
Fandom: Doctor Who
Word Count: 518, not counting quotes from 3.13, 'The Last of the Time Lords'
Based on roleplay with soundofmurder, especially this one