Would security really undergo polygraph tests that often? And would those tests ask questions like "How do you feel about the people you work for?" I'm not saying they wouldn't. I'm saying I have no idea how it all works, but the unsub probably still stood a good chance of getting through that kind of test if he was skilled at controlling his pulse rate, breathing, and stress level. Most people can't do all that to the degree of fooling a polygraph, but you never know. Sometimes the readings on those tests come out as inconclusive, so that result wouldn't completely clear him, but they still couldn't officially pin anything down on him either.
Believability aside, did anyone else find his voice to be really annoying? Yeah, the character was supposed to come across as arrogant and strive for sounding smarter than he really was, but he got on my nerves. It didn't ruin the entire episode for me, but I found myself willfully tuning him out after awhile.