listen to your instructors ,so he wouldnt fail you
here in my company ,only the captain can call "stop"
and for engine fire ,in our QRH "ENGINE FIRE OR ENGINE SEVERE DAMAGE OR SEPARATION" we only use the second bottle if the engine fire switch was still on after the first one .yes we wait 30 sec.coz its on QRH.
and we will do the EVACUATION after the ENG FIRE QRH. you can not trust the light!
for the memo items.the right seat only do the fire switch . in the FCOM "area of responsibility"the throttle and the eng start lever are all belong to the captain .
and also .before the evacuation ,i would tell the cabin crew to evacuate from the opposite side of the fire.