He readied the gun.
"Do it, do it for them, for all those you lost because you didn't have the nerve to do this, do it."
"What are you a fool? Of course you can't, you're a man of peace, 'no guns' that's always been you. At least over a thousand years of time and space without guns and now this?"
"No guns, where have you been? He's used guns all the time, remember that time with the Cybermen, when he had terrible dress sense?"
The Doctor twitched, staring at the eyes of the man in front of him.
"See what he's done, took innocent people, tortured them into submission. Think of the cries for help they must have made, the families that will never be able to see their daughters and sons again."
"No, not now, not here, you're better than this."
"There were Silurians on that spaceship."
"What?"
"Silurians, and he jettisoned them. Those Silurians were alive and he committed homicide, imagine what being subjected to the severity of space feels like, imagine. He had good right to kill Solomon. Every right. He gave him plenty of chances to redeem himself and he never changed his ways, continuing on the path of destruction that lead him into that Spacehsip. Now he has to do this, because if he doesn't make a stand more innocent people will die, if he doesn't do this the people he loves will be stolen from him. He needs to do this because he carries guilt on his shoulders and he's buckling under the weight, but not anymore, this time, this time no one pays the price for his Mercy."
The Doctor, without hesitation, moved his finger towards the trigger and…
Amy.