Poker ruling please.

[pjsales]

Please answer as best as possible.

Blinds are $2000 and $4000 in a hold em tourney. Five players left. Player a is first to act and declares all in for $3800 $200 less than big blind player b folds , player c folds, small blind folds, and big blind throws his cards in a poker action that appears he is folding, the dealer declares he can not fold since the all in is for less the big blind and pushes his crds which clearly went over the card and cash line. Big blind states he is folding but is told he cannot just fold and the hand is run. Question should the big blinds cards have been folded and the all in bettor awarded the small blind $2000 and the big blind $3800 of it???? If obvious fold action and cards go over cash/card line is this a poker action and cards should be folded no matter what stakes are on table??

[HalfSugar]

He can't fold and the hand must play out.