DMU Acapella had to be rescued after being locked in the Queens building for more than an hour.
Three society members society had to ask friends to call security after they were trapped inside during a rehearsal.
Avery Penn, the society’s health & safety officer, said: “There was a moment where we thought ‘oh no, we’re going to have to spend the night in Queens, we’re going to be found by security the next morning asleep on the floor.’”
When the group arrived at 4pm they were told by security they could call them using a phone in the lobby when they wanted to be let out.
After finishing at 6.30pm they found the phone did not work. They were then stuck in the building for another 90 minutes.
Kershia Field, chairwoman of DMU Acapella, said: “We couldn’t get hold of the security office at all. We tried using our mobiles but the security office didn’t seem to realise we were talking to them at all; they just started shouting hello a lot. Clearly the signal was off.
“We tried to rehearse a bit more but were a bit distracted by the fact we couldn’t get out of the building. We called again and got nothing. Eventually we put something on Facebook to try and get someone to come.”
The group were rescued when a friend saw the Facebook posts and went to see security themselves.
Security tried to open the doors for the group remotely but could not when they found the ‘network was offline.’
Kershia added: “We found the whole situation sort of hysterical. I called my Nan while I was in there to tell her.”
A spokesperson for DMU security said: “We’re obviously sorry that they got stuck in there for so long. We did get the phone calls from them but the signal was so bad we couldn’t understand them.
“Every building has a landline phone that connects straight to the Estates building if anybody needs any help and there are posters up with Estates’ number on them.”
The events mirror an incident in London in October when a tourist was trapped in a Waterstones for two hours and had to tweet for help.
DMU Acapella meet every Monday and Tuesday between 6 – 8pm in Queens 0.15.