I've seen this same scenario in play many times in different airports. In some larger airports (IAH) they only have 1 body scanner but way more volume than it can handle, so they will have two other lines going through standard metal detectors. I just stand in one of those lines and bypass the scanner. The last time I asked a TSA guy how to request a pat down and not go through the scanner he got visibly annoyed and started loudly proclaiming how safe the scanners were, its just an X-ray, yadda yadda.