A very unique and easy way to win in 4 player chess

This is how I won so easily in 4 player chess. I took greens queen then my 4 player chess partner moved his bishop to guard my queen. Since green could not use his/her king to capture his/her own pieces and my queen is protecting yellow's bishop and yellow's bishop is protecting my queen it was checkmate. It is a very unique trick in 4 player chess.