Unfortunately Yes, My survival instinct would definitely take over me and pull the trigger. However I would then try to track down the mastermind and shoot him. on his knees, In the back of the head with the same gun.
Unless the victim was a chav or a hobo, then I'd track down the mastermind and tell him I look forward to doing buisness with him in the future.
EDIT: However if he looked like an ok guy and my mind was not all over the place in panic I would ask him if he had any last requests and I would then do whatever it takes to fulfill them.
Unless the victim was a chav or a hobo, then I'd track down the mastermind and tell him I look forward to doing buisness with him in the future.
EDIT: However if he looked like an ok guy and my mind was not all over the place in panic I would ask him if he had any last requests and I would then do whatever it takes to fulfill them.