I went down to the first floor, and they weren't there, but somewhere below the elevator. Thankfully, another man who was in the elevator was a maintenance worker, and he was not only kind enough to radio his partner to find out who I needed to call, he also had a set of keys that allowed me to get back into my room to call them.
About five minutes after calling Physical Plant, a man met me in the basement to open the elevator shaft and get my keys out. He said, believe it or not, it happens all the time with professors and students. It didn't take but another two or three minutes to get my keys back. I was very very grateful.
The moral of this story, though, is to always take the stairs.