I once was stuck in an elevator that had an emergency phone. However, when I picked it up...there was nothing. No voice on the other end, no tone, no background

I once was stuck in an elevator that had an emergency phone. However, when I picked it up...there was nothing. No voice on the other end, no tone, no background noise, nothing. My immediate assumption was that it was a dead line. The head of maintenance indicated the phone was working when he tested it after I got out of there, but if it was working when I was in there, that is a -major- UX issue, since despite having used both landlines and cellphones, I had -no idea how to use the emergency phone-. Theoretically, too, the fact it was lifted at all should have triggered something that led to them calling me back; they never did. I got out by calling the fire department, since I thankfully had just enough signal