7D overheating in LiveView mode

I experienced the flashing "overheating" warning after running Liveview for about 2 hours. Video was OFF. The room temperature was about 30 Centigrade.

If you are wondering what I was doing, I was using the Motion Detect feature in Magic Lantern.

My question is, will the camera overheat if I use the AC adapter instead of a battery?

--
Roy Ward