I heard somewhere else he started crying after a supporter shouted they don't blame him for putting in a request, but we'll never know.
My guess is he just had a very emotionally taxing day. It was probably difficult enough for him to hand in the transfer request, and he probably didn't expect much fight from the club about it. then he's told he has to play anyway, has to share the coach and dressing room with his teammates right after he's said he wants to leave. He returns to the club where he started his career, puts in what may have been his worst performance in a blue shirt, and is then part of an amazing comeback fueled by 3 promising young players whom he's just tried to abandon.
He's a 21 year old who went through all of this in the span of 48 hours...I think a few tears at the end of all that is understandable.