How to unlock this door in Ice "maze" area?

[Cryonixia]

After going through 4 times (twice as Succubus) now on my 5th I still find myself unable to find out how to open the large partly open door in the ice area. It's the one with the smashing spiked walls, the Succubus door on the other side of it, and the wall of ice that must be smashed on the other. I have tried to take over both the large demon, and small ones to find a way into this door, and have searched for about 2 1/2 hours around the entire area for a lever of some sorts (the majority of which was running around holding the Z key). If anyone knows the answer, and would post it I would be grateful.

[Spectrum Legacy]

It might be the red room #2 with 2 crushers each on both sides if you arrive from the succubus door. It's opened via secret room earlier on that contains a painting, that will unlock said red room doors. To get to the painting, from the beginning of said level head to the left slightly uphill and then left again downhill into the ice cave where 1 onoskellis is digging into the ground. There is a wall with purple shine comming through the crack. This wall can be removed by soul sight (or how is it called) and behind is a path to that secret room + painting.

Took me a good while to figure it out and unlock it myself too.