Rotorbrake, doors, seatbelts, engine intakes, awareness and dangers of running helicopters/rotors, position of fuel shut-off valves and battery switches.
Ask them to spray gas extinguishers into engines instead of foam. I have seen someone go nuts with a foam unit before... was only a smokey engine that would have required some minor maintenance, but ended up being thrown in the trash due to the foam. If the aircraft is up in flames, go nuts with the foam!