what is the significance, in scene four, of David’s appearing in the restuarant as François is working, sliding over the wall “like a giant, ominous spider?”

what is the significance, in scene four, of David’s appearing in the restuarant as François is working, sliding over the wall “like a giant, ominous spider?”
In Polygraph by Lepage and Brassard, what is the significance, in scene four, of David’s appearing in the restuarant as François is working, sliding over the wall “like a giant, ominous spider?”

what is the significance, in scene four, of David’s appearing in the restuarant as François is working, sliding over the wall “like a giant, ominous spider?”