[NEED HELP] NetRadiant Triggers/Destructables

Hi, I would like to make a box that explodes when it takes a certain amount of damage, and I also want a piece of ceiling to fall when shot, and crush and damage any players underneath, It should disappear after it falls and respawn after a certain amount of time. How do I make a trigger that activates from being shot, and only shot?Please help!!!!! I need this done by Sunday!!!

You can make the falling piece of ceiling by using the door or elevator functions I think.

You can make the falling piece of ceiling by using the door or elevator functions I think.

The only problem with doors it if somebody's in the way sometimes they will open again, I will make a test map with every combination of triggers and door. Thank you. I'll let you know how it goes.