书上是讲如何用救生锤逃生(沉水里/或彻底沉到水里的情况)不过还有一段话说:leave the car as quick as possible.escape via a side window, preferably on your back with your face towards the roof of the car. Offer help to other occupants. Thus as the car is still above water.
我个人理解就是,既然对于其他乘客的营救都是thus as the car is still above water的情况,那么就是在车没有彻底沉到水里之前尽可能快的逃生。