Same way they became aware of how people drown. [ Jim shrugs. ] For the record: drowning is definitely worse. Takes way longer.

[ Small mercies?? ]

Now, if there's a hull breech, what'll happen is that everything in here will get sucked out there. Like the opposite of a submarine springing a leak. But unlike something springing a leak, you don't necessarily want to try and block off a rupture - spacecraft are built with heavy duty doors staggered throughout the structure that are designed to seal off so that in the event of a breech, it can just basically quarantine that area, let the pressure stabilize, and carry on with it sealed off. If it's a very small rupture and you can shove a dense object on it to give yourself some more time to get out of the area, great, but don't get near it, don't use a part of your body or anyone else's body to try and close it, and just leave.