Doom lever puzzle

There is a lever puzzle in Doom that requires 5 people to complete and allows access to a secret room where the Lamp Post and The Inquisitor's Resolution artifacts spawn.

To complete the puzzle the person to be teleported to the secret room (must have GM or higher Stealing) while four other people stand on the tiles in a circle around the thief. The four people each pull their lever and if the order is correct the thief is teleported, if not then rocks fall on your head (high resist armor recommended).

To help you solve this puzzle in the shortest time possible, I've made a handy guide. The idea is that the four lever pullers are labelled N, S, E and W and the order they should pull the lever in is given as a four letter code, e.g. NEWS. Depending on how many levers are correct, then follow the appropriate leg of the tree. Yellow boxes are combinations to try, the blue boxes list the combinations that could possible be correct at each step.