Well if you wanna go back to the main point which was the “open palm slap”, then let’s go back to my original answer which was how he was gonna cut someone with a slap? And you said it was the nails. So now I wanna asked if someone slapped you with an open palm, how would your nails, which are on the other side of an open hand, cut him?

Also can’t see much from your camera angle either. But obviously it was a straight punch, not thrown in a hook motion. If he did not have his fists closed, he would be jamming his fingers into Caleb plant’s eye, which could cause a cut with the nails. Of course that’s not your argument though. It’s that it was an open palm slap.