Oh and when in wrecks, don’t touch anything sharp, carefully make sure you know what’s above you (don’t bump your head, you can knock yourself out). A helmet or a 5mm hood will go a long way towards basic head protection but really... be careful. And don’t touch anything that could hurt you.
Lastly get reallyyyy good at frog kicks and buoyancy bcuz just like in a cave, you can stir up silt. This can make it hard to escape, even with a reel/line