Hmm... let's see. Enclosed space made entirely of synthetic and composite materials catches fire and fills the ship with toxic chemical smoke.
Computer: Should I wake 'em and get 'em to fight the fire..? ...or jettison them..?
Not a hard decision to make.
Also, we haven't yet seen anyone emerge from hypersleep and be ready for immediate action. Even peak condition marines get out of their chambers and feel at the very least a little unprepared to deal with such emergencies.
Isn't the Nostromo at least 70 years older than the Sulaco? I'm guessing safety standards and tech will have changed during that time.
-Windebieste.