How should I punish my cat for misbehaving and giving us so much anxiety and tension?

Don't spray him or anything like that because since it has happend, he will not understand what he has done wrong. He didnt intentionally break the rules but I can imagine how you must have felt! Maybe don't let him out today at 7pm. Or you can try next time you let him out do it before he eats, that way he will stick around waiting for food.