That wrist grip looks rough. The angle that his hand is in is not the same as if he had to hold the wrist without the gi. Looks like you could just yank your arm out. The weakest part of the grip (gap between thumb and fingers) is the fastest easiest natural way out. Looks like the only way out is the easiest way out. Might have a better chance gripping if they have a mma glove on
Try it out and let us all know, if no one else tries it first