JT as well sheathed his right blade, before his arm started to fade away, only to be replaced with the fake-skinned arm he had previously used in combat. He had experience over Ren with grappling hook augs, it was the first Aug he ever had installed, and came pre-installed when his big adventure all started. And so he lunged at Ren with his left blade, swiping from the right to knock her weapon away. JT was ambidextrous and his writer is a lefty, so he definitely had some advantage.