Rear dome light stays on and alarm randomly goes on?

[Goodison]

2002 RX300

Hi everyone, this just started happening today. The alarm turned on for no reason in my driveway when I was in the kitchen eating breakfast, I didn't really think much of it and I turned it off and later drove to work.

At 2am, about 30 minutes ago, the alarm turned on again and I noticed the rear dome light was on, the light closest the lift gate. I used my key remote to turn the alarm off, but the rear dome by the back gate door was on and would not turn off. I waited a good 15 minutes and it was still on. I changed the center dome light to off to see if that would help turn it off and the rear dome light still stayed on. To not drain my battery, I unhooked the battery and the light finally turned off. 

Bad door sensor on the lift gate? Fuse? Battery is relatively new so I don't think it is that? 

Thanks everyone!