Well whether I would go to jail would be based on the law and my rights to defend my life and home.
As for the rat or mouse, well if it didn't know any better, it isn't going to make that mistake again when it's killed, as for all the other shit, no I am not going to go out of my way whether it is a thief or some idiotic kid breaking into my house who has a cold and doesn't know any better.
Their results might wind up being the same as the rat, and no I wouldn't feel bad about it, I don't know nor do I care what their problem is, or why they are intruding into my property. I would rather that it doesn't turn out that way, but I am not in control of all things, like anothers choice.
And for the record, while I wouldn't go out of my way to harm an animal or person, rats and mice I especially hate, so them suffering or being put out of their misery doesn't bother me in the least if they break into my home.