Creepy!

Heh, something weird happened yesterday. :D
I was in the kitchen making a peanut butter sandwhich, I was alone.
Then as I walked out, when I was just stepping out the kitchen, the microwave oven beeped.
It beeps a few times when it stops heating up something and when you don't take it out immediately it does one beep after every minute or so. And I heard one beep. I immediately thought my brother had something in there and had left it. I turned around and went back. It all happened really quickly so I know no one else had been in the kitchen while I was there making sandwhiches and when I left the kitchen for a couple of seconds.
I walked over to the oven to get whatever was in there and I saw that the microvawe oven's door was open and there was nothing inside. Freaked me out!
I just got off the phone with my mum and I asked her if the thing makes noise when the door is left open and she said no, it doesn't do anything at all when the door is open, for safety reasons.
Creepy!