I suppose at this point to keep describing what I see in the 2:07 - 2:09 exchange is pointless. The only explanation I can come up with is that Szymon's blade hit Carlos. You disagree. Fair enough. Even at 720p, YouTube video is hardly of a high enough fidelity to allow us to resolve this disagreement.

By now I think half of the views on that clip must be from me...
Jesse Eaton wrote:Assuming he is wearing exactly what he is wearing, it isn't enough. Consider that you are gauging from a third person perspective but he is on the other end of the strike.
I'm assuming that "injure" refers to the theoretical wound a strike might have caused if the weapons were sharp, and particularly wounds that would have a significant effect on a combatants ability to continue the fight -- a highly subjective measure. If something else was meant, please correct me.
It seems Carlos is wearing a gambeson with some manner of shirt (plastron?) underneath. Depending on materials, this might prove very hard or near-impossible to cut through effectively (going by Mike Edelson's tests
here), meaning this logic might lead to discounting almost every cut to the body and arms. Which is fine too, but different to what I have understood the basic judging standard to be: would such a strike with a sharp sword caused a significant injury, assuming clothing provided very limited protection? By this latter standard, for all that I can tell, the cut seems more than powerful enough. Though again someone with actual experience judging longsword bouts would know far better.
As for taking his word for it, people much smarter and more experienced than me have pointed out the various reasons why good, impartial judges are a far better alternative for figuring out what happens in a bout than the fencers themselves. That doesn't mean I think I am good, or impartial, or indeed a judge, or that I doubt his word (beyond my general skepticism) but it is true that things look different from within than from without.
To be sure, at this point I would not be hugely surprised to learn that I am seeing the whole thing completely wrong. I do not wish to be belligerent, I would simply love to learn why it is that we are seeing things so differently, and what is it that's actually happening in that video. Figuring this out would appear to be of a fairly high importance, seeing how many people find the "AEEA-style" so alien upon first seeing it -- if its practitioners really are as superior as you apparently see Carlos as being in this freeplay, it should have quite an impact on the way the rest of the HEMA world does longsword.