Members of the US Marine Corps are a bit more likely to be involved in a helicopter crash above the sea than most of us, hence they get trained on what to do should it happen. Here, you can pretend you're a tough marine, while on the internet from the safety of your black faux leather PC World chair.
The video, called helicopter underwater egress training -- because we think "egress" means getting out in a hurry but doesn't sound quite so terrifying -- shows what they do. It involves holding their breath and undoing seatbelts in a hurry, but not in so much of a hurry that they flail about screaming.
Although being as this is just a test, there's a nails-hard guy just milling about in a vest underwater while all the shit goes off. His job is to make anyone caught screaming about mummy do 50 underwater press-ups. Also, seeing as it wasn't a real helicopter crash, they didn't have to deal with bent metal and fire and they weren't already dead on impact from smoke inhalation. Pretty easy, really. [Popular Mechanics]