Just before the big head, if you go to where you offered blood, to the immediate right of that circle, is a few pressure plates with akavir symbols on them. What is the purpose of them? Makes me wish it was a puzzle to finding unique akavir armor and weapons.

It's a trap!

Just follow the Akaviri symbol for Dragonborn and you'll be fine. Nothing really happens if you step on them anyways.

well not the traps, but near the entrance there are random buttons that dont seem to do anythig, they are just there o_O