If one of the slaves from the hallway above enters it halfway only, or if the "surprise" slave spawn in the descending elevator fails (i.e. the slave tries to get out of the moving elevator and jams it) then yes, that happens. Sometimes you can frag it with the grenades in the secret cupboard in the first hallway from spawn room.

Ideally add a monsterclip, but just adjusting the slave spawns works well enough.

Fortunately it didn't happen to me and I got all the way though the map.
It is a pretty fun map but is a bit of a hard slog if you play solo.