You can trick the companion to disturb the mummy and the that poor guy will get the curse.
Mummies are really one of the scariest thing in DF right now. I can swear they break all the laws of physic. They... they are already everywhere I try to go.
I was sneaking with my two companions. I found a tomb and wnet inside. My companions were butchered by the mummy (I was sneaking nearby and the mummy didn't saw me). I took my turn to leave, and when I exited the room, the mummy stood in front of me.
I went back to the mummy's chamber and found a stairs. I saw how the mummy kept appearing in my small field of vision - I didn't had been spotted yet, even the zombies just stood silently. I managed to climb some stairs upwards, and there it was. The mummy was already there. I tried some other ways, but the mummy kept coming after me. I didn't ever saw it actually moving, just appearing into my field of vision when I moved. It could have moved very fast outside my field of vision and get always there before me, so it seemed like teleportin, but I doubt it. Mummies aren't that fast.
At this point I had completely forgotten all the sweet loot I could get, and just tried to get out of that hellhole alive. I get caught in a weapon trap, which sent me down into ground. I crawled forwards and noticed once again a dead end. When I turned back, the mummy finally spotted me and killed me.
Damn scary. I've encountered similar behavior with catacombs mummies, too.