Well you normally don't have perfect information. Imagine you're woken up in the middle of the night by a window breaking, you hear somebody coming down the hal

Well you normally don't have perfect information. Imagine you're woken up in the middle of the night by a window breaking, you hear somebody coming down the hall, and there's a strange figure in your doorway. In the worst cases you could be moments from death or sexual assault, or perhaps there's no violent intent at all. Are you obligated to wait until you have evidence of violent intent to use a gun?