Before opening an exit, quickly look through a window
to check outside for the following:

1.
If smoke is so thick you cannot see out the windows, be aware that the aircraft has entered water.
Be prepared for the possibility of immersion by removing the floating device from beneath your seat.
The life vest will inflate only in an emergency following instructions.
2. 
If you believe that there is fire anywhere near the aircraft, remain in your seat and calmly notify qualified emergency personnel. 
Do not attempt to exit the aircraft, or the fire will follow you. 
The oxygen masks will descend from the overhead compartments to assist you with breathing.
3.
If debris and obstructions outside the aircraft are preventing you from exiting the plane, find another exit that is closest to you. 
If you are sitting near an exit row, be prepared to assist the other passengers through the debris.
The exit door will assist you in protecting the hull of the aircraft from debris/obstruction trauma.