Not to make a mountain out of a molehill...
I would not worry if someone unexpected walked by and happen to peer "into" your vehicle while you were unholstering and securing your firearm to comply with a premises issue...You are making a reasonable effort to comply with the law, and if someone peers in, thats almost like opening a door to a closed room where you are at...I wouldn't sweat it too much...Just do all the handling as safely as possible...
If it means that much to you, I would make a really good scan of the area watching for folks that might come up between your vehicle and possible look in as they pass and see what you are doing...
I don't much trust putting a firearm under a seat or in a glove box or center console because it just doesn't secure it enough for me...I'd rather slow them down by buying one of those "breadbox
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thin metal" vehicle gunsafes we've been talking about since day one of this forum...Links are all over ther place, and they are a good buy for what you need them for...I'm buying a few for Christmas presents...
2 levels of security sure do tend to slow the average smash and grabber down a bit when you have to...