In the Radac's Forge section of Bamz-Amschend, the armory door is locked and requires a key. I don't remember it requiring a key in vanilla Morrowind, and judging from other posts about the Tribunal MQ it should be possible to get past this point in the "Blade of Nerevar" quest. (i.e. There were bug reports from 2015 about the location of the Pyroil Tar.)
I've looked all over the place and can't find the key. I couldn't find any information about such a key existing either. Since there's only a single satchel charge available (in the Hall of Winds) without entering the armory in Radac's Forge, the Tribunal MQ is essentially broken for me. I'm not sure if the key was lost or sunk through the floor, or if this room was purposely locked because the latter part of the Tribunal MQ isn't finished enough.