How to access the exit chamber in TNT Evilution level 32,
Caribbean:

Background: The Exit chamber is located near the middle of
the north edge of the map.  The chamber is sealed by a pair
of doors/barriers, which will open momentarily when certain
switches are activated.
There are a few methods to get into the exit chamber, this
is the easiest:

Just south of the Exit is an oblong pit in the ground with
2 teleport pads.  Step on to the white (western-most) one.
You'll appear on another white teleporter pad on a raised
shelf to the left of the Exit.
Take a step forward and turn left to face a switch on the
wall.
Do the following as fast as possible:

1) Activate the switch on the wall and step left, back on
   to the teleporter where you just appeared.
2) When you appear back in the pit, Run forward (remember
   that "Run" in PC/Mac Doom games is typically enabled by
   holding down the Shift key) and turn right to face the
   switch near the red teleporter, and Activate it.
3) Step backwards onto the red teleporter.  You'll appear
   right in front of the Exit door.
4) Run forward into the Exit chamber before the barriers
   close.

Done!

PC Doom players can access a demo of this level that shows
how to get into the exit chamber, by clicking here.