New Car Dash Electronic Buzzing Questions?

Hi all,
Today brought my new 07 400 mile baby to get new tint installed. I was concerned that they would kill the battery leaving the doors open so I made sure I turned the overhead door light in the off position.My question is when the door light is on or any load on the battery when the car is off such as running the radio or lights on am I draining just the car battery or the hybrid battery pack or a combo of both? I have read other posts about a weird buzzing in the dash and I heard it in my car today. When I picked up my car sure enough the battery had just one purple dash on it. When I started to drive away slowly I heard a buzzing or chattering under the dash right in front of the steering wheel. Briefly upon acceleration then stopped. This buzzing continued upon multiple take-off's until the battery indicated all green bars and then it stopped so its some kind of low volt relay chattering going on there.Sounds like very faint arcing or a relay thats bouncing & trying to latch. Everything--- all lights air & radio worked perfect during this buzzing. I'm an Electronic Engineer so I can't wait to get my hands on a print to this car.Never heard this buzzing before. This is the first time I let the batt go low no fault of my own. Not sure why..maybe they had the radio jamming while they worked. But it's a low volt problem and all you peeps that are hearing buzzes you ain't nuts! That will be the last time my baby gets low volted if I can help it. Man. I love this car though!