Lair of the Emayu Witch help

[mtwang1]

I'm at the last level (I think) of Lair of the Emayu Witch and I'm at the part where you have the lever floating in space outside the room, & I can't figure out how to get the gate open.

I've tried:
Spark spell
fireball
compress atmosphere
reveal map to see if there is a secret passageway???

Can I get a hint? Am I looking at the wrong place?

[Randomizer]

The lever is accessed from another room. If you talk to the witch then you are close.

[Jennuh]

Have you met Biezel yet?

[Vroqren]

[+] SPOILER

You do not need to open that gate (if you're in the room with the staircase). Go up the stairs, and over to Ulgolek (the tree), and there is a trapdoor that leads down past this seemingly unpassable gate.