I don't think Lockette is gone. Besides special teams, the guy does have a chip. Remember his blocking on Beast Quake 2? He's a team player for our guys
I don't even know if Bevell is gone. There is likely a pass play in there at the end. Can you imagine going four downs rushing and not getting a TD? Then what? I agree with most I still would have had Marshawn rush another time
If you want to blame someone for that last play, I'd blame Russell.
In the end he is the one on the field executing. I don't think he was dialed in and he didn't finish. As the game went on his passing got worse (remember the drive before? His 3rd down pass to Lynch was wild?). Had he been focused I think he would have realized where the defense was and thrown behind Lockette a bit instead of leading him into coverage. Had Russell executed that pass we would all be saying how genius it was to pass the ball when they were expecting a rush.
As far as being dialed in: And even there, I'd say the team as a whole was not as dialed in as it could have been. Maybe they were spent from the Green Bay game, who knows, they just didn't have that killer instinct that they carried the last 8 to 9 weeks.
I trust John and Pete to make the right decisions. They'll figure out what the mistakes were and figure out best how to fix them whether it's letting someone go, looking for something specific in FA and the draft, and what not.
That being said: I'd be surprised if Lockette was gone.