I would use a
plrdistwithin=x to see if the player is in the room.
Then you don't need a trigger, since the character can trigger himself.
You would need to adjust the distance according to the room.
This would be his AIMAIN...
:state=0:state=1
:state=1,plrdistwithin=200:timerstart,state=2
:state=2:incframe=14
:state=2,timergreater=280:state=3
:state=3:runfpidefault=2
I tried
animationover=x and
frameatend=x and
framebeyond=x y
None of them worked for me, so I had to use a timer.
That will result in different things depending on computer speed.
I know there is a better way to do this, but this works for now.
Add a sound effect like an explosion and you complete the effect.