While puking, you have your stomach exits open for exiting material but not your lungs open for exiting air.....so you can blow out your lungs if you ascend while "holding your breath," thus AGE, etc. Clear enough, or is more explanation needed? It is an IMPORTANT point, so don't just let it slide by. Understand it.This seems to be a common commit to ensure you're not rising, stay at the bottom and don't try to acend, etc., Which I will follow this advice but I'm wondering the logic behind this precaution?