Stuck in The Hollows (Griever's dungeon) (end game)

[Van Silke]

I can't seem to find my way back, can anyone help my case?

I found a bunch of blue crystals, crushed them, fell down a hole with a chest, then the staircase turned out to lead to the first Griever encounter hall. Unfortunately, I don't know where to go from here, because the door is closed.

There was another door past the turbine that's also locked. If I remember correctly it would lead me to the boss room which had a teleporter, but I can't get there, unfortunately.

[sebo]

it's hard to say without any screenshots of the area you're in..
look through a play through, this is a 6 part video so skip to the part where you are..
https://www.youtube.com/watch?v=pr8SwI5uPeM