Anything is possible if you honestly put your mind to it.

As for if you'd be ever be able to kill someone. Some people aren't and that's a good thing. If I could I would avoid it myself, but sometimes a situation might call for it if for example they are doing something where there is no other choice. It is deciding their fate but it can also mean you are letting them finally have peace.

[And yes he tries to think of the positive to having to kill someone.]

You just have to hope that never happens.