ok so two things, one remember we talked about her walking in on them in the middle of the duel causing Jasper to lose...and two the reason Jasper is using his right hand is because he is afraid of further damaging his scarred shoulder from the bolt of lightning when he was younger, but I was thinking in occurrence to this, Jemma tries to help him and asks him to use his left hand and he becomes better....she is trying to help so he can forgive her or something, and asks him to use his left instead cause she can see how sloppy he is using his right .