If the maintenance man saw both bodies, then why didn't he see that the front door was open?
Given that Betty was by the front door and he saw her through the window?
I'm not very good at spatial awareness imagining, so maybe it's a geography question. But it's confusing.
I've told this story before but it always seems relevant. I was at a friends house when he was shot and killed outside his home. I saw it happen, I called a friend, waited for cops, as soon as I saw one I calmly walked out the front door and went to my friends house. It wasn't until the next morning it even hit me what the heck happened. I was in literal shock from seeing his body, so I can confirm your brain doesn't work the way you think it should during an emergency, sometimes it goes right to fight or flight mode and you honestly can not control it. I wouldn't have ever thought that I would run in that situation but I did, and I swear it felt like I was watching myself not in control of my body at all. We don't know that the maintenance men didn't think someone was possibly still in the house, or what was going through their heads. I can not and will not fault before for how they react in an emergency because first hand I know how odd your body can react.