Same with bombs that make noise. Poisons are legal at any time. Note that you can attack through an open window. Attacking anyone else by any means is considered attacking an innocent bystander, which is bad. Very, very bad.
Accidental death is different.
But if player A intentionally kills player C, player A is penalized and player C remains in the game. Player A will always be penalized if he kills, or tries to kill, someone who isn't in the game at all. The list of weapons, of which I have several copies, classifies everything as Class A, B, C, or D. Players who come up with ideas for new weapons must clear them with me. And not all A and B weapons are legal.see below. If you are making an attack with a weapon, there can be no more than two witnesses to your crime.