They do have rules about angles. Camera work is supposed to trick people to think it’s a straight on shut when it really isn’t. Just like with “Hollywood punches” which miss their mark by quite a bit, but at full speed fro the angle its thrown, look like they were a direct hit.
But rule #2 or #3 in live firearm handling — always know what is behind your target. You might be shooting into random space however, a live bullet will continue to travel beyond the couple of feet within your field of vision.
Then again, we don’t expect an actor to know this if he has never fired a firearm nor is that skill set required.