I have heard the stories about old ladies lifting cars clear off the ground to save trapped children, and it set off my urban legend detector. I thought it must be a lie or at least an embellishment.
I can certainly see how maybe a healthy individual might be able to summon the strength to lift up maybe a corner of the car as you suggested.
I do wonder, though, what kind of damage they'd suffer as a result and how long it would take to recover. I'd imagine those "limits" adrenaline helps us break are there for a reason, right? I've read that we tear our muscles down each time we work out, just for them to be rebuilt in stronger form.... so is it too much of a "stretch" to suggest that adrenaline could cause us to snap one of our muscles in half or something?
Not necessarily snap in half but damage? Sure.