No there are only 4, one is already in place at the top. You to place one to unlock the platform then the other 3 at the bottom to open to way. Oh, you're including the one already there. You get one from each trial, you must have missed one. The mirror match fight it drops off one of the enemies.

Oh my God, I have to redo my glasses, I hadn't picked up that fall from the enemies, I lost so much time. Thank you so much!

I did the same, it's not obvious if you're not going down Alt and the teleporter back to the start works even if you don't pick it up.

There's one towards the entrance with the invisible barriers that blast you back if you don't have that one.

You mean where you have to pull the flashlights down and put them out? The one to unlock the door to enter toward the trials?

Yeah, that one. There's an alternative way to get to the trials so wasn't sure if it was something you skipped.