What medical training does to your nervous system - and why it lasts a lifetime This past week, I was in an airport, returning from a fantastic family vacation. I was as relaxed as one can be whilst sitting and awaiting one's boarding call. Then, from somewhere nearby, there was a beeping noise - a coffee shop's electronic coffee maker, perhaps. It wasn't a loud beep, but to me, it may have well have been bomb sirens suddenly piercing the air. I jumped, startled, and whirled around in a panic.