While evacuating from the building during a fire, Alfred turns on the building fire alarm, shuts all the doors behind him, and rushes to take the elevator to the ground floor. What dangerous mistake has Alfred made?
A) He took the elevator to the ground floor.
B) He shut the doors behind him, making it hard to return later.
C) He stopped to turn on the fire alarm.
D) He evacuated instead of sheltering in place, away from the fire.