I doubt it. Too much of a risk that she might see something suspicious in his room and report it to hotel security or LEO.
Good point. I guess if that’ sex was what he wanted, he could have rented another room just for that.
On the other hand, it sounds like he had a suite with multiple bedrooms. He might have kept the guns hidden in one of them until he was ready to start the massacre. If I were him, I’d also be concerned about hotel personnel (maids) coming in the room. They sometimes do, even if you give instructions to be left alone.