Clive Carter, 35, is charged with murdering Khanokporn Satjawat at the Clyde Auditorium in Glasgow on November 12, last year.
Carter, from Motherwell, is said to have repeatedly struck the victim on the head and body with a fire extinguisher.
He had earlier pleaded guilty to the culpable homicide of Miss Satjawat and has lodged a special defence of diminished responsibility, but the Crown did not accept this plea.
Yesterday, nursery worker Stephanie O'Brien told the court she was staying at the Holiday Inn in Stockwell Street with three friends when the zip on her skirt became stuck.
Carter, who was working as a security guard, tried to fix it but it broke and she decided not to go out.
When she was alone in her room, she said she heard a quiet knock at the door. When she looked through the peephole she saw Carter standing holding a fire extinguisher.
She opened the door a little bit and Carter told her he was responding to a report of a fire in the room.
Eventually she called her friends and locked him out, she said.
Carter is also charged with a breach of the peace by pretending he was reacting to a report of a fire and entering her room uninvited.