"I have nothing against ass kissing. The literal kind, anyway. The metaphorical needs more prep and lube." He's absolutely on autopilot with the innunedo and snark.

When Jack comes down the stairs, gets closer, he takes a half-step back. There's something in the contradiction between the way the older version of himself is obviously trying to help and the fact that help involves killing himself that makes processing a little hard to handle. Torn between wanting to reach out and that still-there-instinct to protect himself and fear death.

Half-step, one foot back, is all that happens though, before he plants himself where he is and nods. "I've got it." Because he has to control it, it has to be him, and he has to know himself, one way or the other. Not knowing is worse than death. He doesn't waste time, though. He just lifts the gun, turns it on himself.

He's not familiar with the gun, but he's still a decent shot. The only real issue is that when he pulls the trigger he's flinching away from it, already. That means the shot's not completely on target and he's not dead when he hits the ground. Unconscious, out of it, adding gore to the TARDIS, and dead within thirty seconds, but not instanteous.