Crypt Question need HELP

I am in the Crypt killed both Skeleton Warriors the one was a Mage who protect the Lights i need to use on the Braziers to choose my way ,Wizards way or warriors way but i can t get the Light because the Stairs up to the Lights slip down in the Ground when i go near to them . I carry both Crystals on me but i cant get up there ( need a hint please help me

Try both crystals in the slot on the wall near the stairs - only one of them will fit.

Look to either your left or right on the walls of the room in which the stairway disappeared. You should see a horizontal slit in the wall, about the eye-level of a gnome, to put the crystal into ("use" crystal). That should bring the stairway back. You'll need to retrieve a figurine out of the fire at the top. Look for some of the walkthroughs that are posted for the remainder of the trial by fire, as they can be tricky (I've never been able to make it through one of them, the warrior's, I think).

Use a crystal in the wall receptacle in either room. BUT carefull... you can only chose to follow one path or the other. The other chrystal won't work after you have made your choice.