I am a total newbie in chess. I was playing with an ~intermidiate computer~ as White and made a pretty stupid mistake by playing Bf4. I waved the bishop goodbye, yet Black's rook did not capture it. Was there any good for the Black not to? The white pawns are moving downwards here. As far as I know, the pawn cannot move back to capture, so I reckon that the bishop to have been 100% unprotected.
[FEN "5NK/2r3P/5PBP/8/1B1P/1k/3R/8 w - - 0 1"] 1. Bf4 Rf3