[ She may sleep like the dead but he's still on edge from the raptor encounters in the hall. Sleep may happen but that doesn't stop his senses from being on high alert and there's no way he can sleep through the screech of the PA system coming to life. He wakes with a start, every muscle in his body tensing all at once at the sudden noise.
No sense in waking Rebecca at this point (and he's not sure he could if he wanted to) so instead he just slides out of bed to investigate. ]