He's got several different targets, it looks like, including the people that put a spear through his father's leg and left him limping for the rest of his life, the Trevelyans.
One of them invented an odd, rolling limp that struck the rest as supremely ridiculous, and several of the boys lay down on the ground and rolled about in laughter: Philip was completely scared.
It's interesting to go and read about the various theories of how debilitating Uh, Philip's various maladies were, uh, but he, he certainly had at, at the least a limp, maybe it was even worse than that.