correction - after watching the walkthrough, i realized that the favor is supposed to be called after shooting the guard. problem is, if you shot somewhere above the chest (like i did, the head for instance) the mask doesnt come off, the guard doesnt duck (shooting forever), and you dont retreat to cover, breaking the game.
pretty sure davidjk66 was experiencing the same bug im looking at now.
if you do not collect the 'good shot' favor before the guard has you pinned down (after you collect the favor from the cats), at least the button for the 'good shot' favor does not cause anything to happen on the surface, effectively stopping progress.
 "Another Small Favor"){kind=icon}