I've been warming to him ever since he started standing up to Bart after the Later episodes. This is the second time he's saved a life now -- Bart drowning in the bath in Later, who appears to have forgotten that and immediately reverted to treating Jonno like crap once they got home.
I like that while he was with Ruby, and he checked to make sure she wasn't too hurt first, it was Sinead he saved first as she was in the most trouble, and that he comforted and reassured her when she was a wreck by the side of the road before rushing back to help the others. Little hero IMO.