First, it is very important to know that the most vulnerable time for a mishap in aircrafts is during landing and take-off. The cabin crew is given specific instructions to keep passengers safe. In case of an emergency, the crew has only 90 seconds to evacuate the people on board.
So preparing for any kind of emergency before hand can help save vital time and those 90 seconds can be the difference between life & death.
Same reason why they make only Able Bodied Persons (ABPs) sit next to emergency exits.