My impression is that, when he said he felt like he'd been looking over his shoulder for the last five years, it was a comment about how the 2013 PACE trial results and their controversy had sucked all the oxygen out of the room during that period, forcing them to look backward and making it difficult to progress on any other front. PACE had become an albatross around their necks. In the end, though, it mainly seemed like a way of saying, "Let's get beyond the past," without actually taking a position on it.
I could be wrong, but that's how I interpreted it.
The problem, of course, is the degree to which PACE continues to influence the medical community. Not just because it may actually harm patients, but because it also promotes complacency in a sort of "ME/CFS? Problem solved!" kind of way.