Hmm first thing that comes to mind is HVAC guys installing an air conditioner in my house. I was working night shift so I got home at 7am, and they were scheduled to come at 8am. They showed up and prepped and I told them I was on night shift so heading to bed, but to do whatever they need to do and not worry too much, just that I won't be around if they need me for anything. I went to bed and I remember hearing a concrete drill going pretty much under my room to make the hole through the brick for the freon line going outside and also recall hearing some pipes and cables being tugged through the holes that I also heard them drill in the joists, and don't really remember anything after that. Woke up around 3-4pm and went to check out their work as they were gone for break. They showed back up to finalize while I got the automation stuff working so they can test fire the unit.
I'll easily sleep through road construction or snow removal too. It's funny to wake up to find half your street is dug up. lol.
A murderer who also happens to be a machinist could probably build a gun in my room while I sleep and shoot me with it.