Although the actual “transaction” didn’t seem that scary, as the day went on, my senses became alert to peripheral threats. People in peripheral vision–if they turned as though to come from behind me–suddenly became a threat in my eyes.
I had a similar sense of shell shock when in the middle of gunfire in the Albanian civil war. For weeks in the USA I would instinctively react to sudden noises even though intellectually the source of them were harmless.