I had a look at the video and I reckon Peter had looked at where the majority of the money was being traded and how it had traded prior to that point. I couldn't see what caused the brief jump outside of the main range but would suggest a "lump" hit the market to cause the blip. What goes into the market generally comes back out at some stage (unless it is a straight lay) so the market does return. Obviously this is supposition on my part based on what we can see in the video but I think Peter had looked at the trend and probably thought the move was a temporary one and so held his position.
I am sure Peter will probably add some info on here to explain why he held on......that's if he can remember the detail having recorded so many videos.