Odd battery kill

[4.6toddy]

Hello all, new to BMW ownership and to this forum. Have read a lot and learned quite a bit from here already.
I purchased a 2002 X5 4.6IS after finishing a lease on a Hummer H3. Anyways here`s an odd one since i got it in February

On about half a dozen occasions I have come out to find the X won`t start. click click on the ignition, obviously dead battery. half an hour or so on a quick charge and it roars back to life. The battery and alternator test ok. When it comes back the same symptom is always there. the 4 way flashers are on, and the interior light forward of the sunroof is on.
I suspect that i might be bumping the 4 way button when i get out and reach back in to grab my coffee out of the cupholder as i`ve done this and noticed it a few times. but they shouldn`t be enough to kill the battery. is there something possible thats causing the overhead light to come on that i`m overlooking?

here's a few shots of the X including the aftermath of deer hit 10 weeks into ownership. I get it back from the body shop tomorrow or Tuesday

Thnks for any help on my mysterious battery kill