Therons Quest Remix for RTC

[the master]

I am on the caves level and have got to a place where you have to place pyro into a machine that fires fireballs. Nearby is a room with 4 levers. Your onviously have to push the levers to set the deflectors and kill the spiders. I have killed all but one but can't work out how to get to the last one. Does anyone know the sequence for the levers. I do have a scroll which says "Manual" in my possession and shows the symbols in the room and another 2 symbols outside. Any help appreciated.