Did the girls have to act so stupid?
The one girl kept nagging about Michael getting drunk, about how they need to get out of there, about she is the one with a life.
Then the other girl kept acting stiff and anxious, being claustrophobic, with flashbacks to the accident.
The movie had a good enough concept. Being trapped in a sauna by itself was suspense enough. They didn’t need to have the girls act so stupid to create more suspense.