I was going to show a house once. I always got to the properties early to get things ready. I got to one and got in. When I suddenly heard a noise in the back bedroom. A man came running out and broke through the back screen door because he couldn't get it open.
At a different property I was actually doing a BPO on I did a complete inspection inside. I was on the phone with my husband joking about how the attic ladder was down a little. Next think I know I hear a sneeze coming from above me. I got out the home FAST and called the cops. Turned out the homeowner who had been foreclosed on had been sleeping there at night and had climbed in the attic when he heard me coming in.
I actually had a couple other things like this happen over the years. All funny looking back on them, but nerve racking when they actually happened.