I've been riding the Montgomery bandwagon about as long as anyone has but this game really soured me on him. The blown blitz pickup earlier already had me questioning if his head was in the game, the decision to take it out of the end zone was inexcusable. Like the anon player quoted said Montgomery just decided "to do him" fuck what the coaches want.
I don't know if you cut him but I'd atleast try and get someone else ready on the practice squad if needed, and make Montgomery ride that bench for atleast a week or two. Until someone gets hurt or they absolutely need him to play. He's a free agent at the end of the year i imagine he'd prefer getting cut/picked up somewhere where he'll get more of a chance to showcase and get paid.
I'm hoping/expecting Montgomery to apologize to the team this week and for them to bury the hatchet, but if he becomes a locker room cancer because he's not getting enough playing time just make an example out of him.