According to the AAMVA CDL Manual, what is the general rule about keeping students on a school bus during an emergency or impending crisis?

AAMVA CDL Manual, Section 10.3.1 – Planning for Emergencies, p. 10-6

Panicked, premature evacuations can put students in the path of traffic, fire, or other hazards outside the bus that are more dangerous than staying put. Knowing the default is to stay unless there's unnecessary risk helps a driver make a clear-headed, timely call instead of an automatic one.