IMO, he knows it is over after he has murdered her, when he's wearing the red striped shirt, when he comes out of the opened hotel room door (after a few seconds) during the pathetic door knocking, limp-wristed scene. May have just been checking out who may have been around. Had anyone heard anything, been or is in the corridors? Simply, freaked out. In that videotape, he's stalling to see if anyone's coming, waiting, making sure.
There was nothing for him to do. Can't remove the body, can't clean the scene up. It's been his hotel room for two weeks. She was seen coming in, videotapes, etc. All he cares about is a few hours head start and when eventually caught, the best explanation/confession he can muster (cause he knows he's doing time for her death), which he knows will be next to impossible. But what's he gonna do? He's not stupid. He's a socio/psychopath. One does the best he can do. Try to move forward. Say what you can say. Smoke and mirrors. Whatever it takes. He adjusts and adapts well.
Believe he returns w/employee just to attempt to establish that she was still alive at that point (She wasn't.). Her body would not have been visible from what we had discussed earlier re room layout, location of body in room, etc. IMO, he does not want the employee to discover/see the body. No way. Otherwise, he would have moved it to the room's hallway. On the videotape, you can see his boldness (and pathology) - actually, leans against the hall corridor wall as door is opened. (Would I be doing that with a dead SFR in the room?). He is trying to establish a living, breathing SFR. He'll worry about the forensics later.
As JeanC confirmed recently, there's cameras all over Peru, not to mention he's well-traveled, grew up with technology, etc. It's the only time we see some panic and fear from him, other than, perhaps, upon arrival in Peru and when paraded in front of cameras for photo shoot. Cause, like a good socio/psychop - it's all about him.