Well, for starters it was a training torpedo (lump of concrete instead of a live warhead and motor) so it's pretty much a non event already.
Secondly the torpedo launcher is actually on the main deck (above the waterline) so it will fly through the air before it hits the water.
Thirdly during an exercise if you hit 1 too many buttons you will actually fire what's in the tube.
If you're doing torpedo drills to train both the loading crews and the gunners then there is a fair chance that someone will get excited and either press the fire button thinking there's nothing in the tube (used to doing drills without weapons being loaded), or forget that the system is live when they hit the fire button(knowing there is something in the tube but forgetting at the key moment maybe). At least they know the system works though, always refreshing to know when coming out of refit
