How does white go from this

To

To this

I don't get it sometimes like that first position all you have to do is give a rook check and win the knight. How do 2400s make these mistakes? 

There must be something about their games that gets them to 2400 though. It can't be arbid. 

I wish I knew what the sub modular level chess skills that are at play here. Pretty sure these guys do one thing better than the other so even though there are holes in the games, over all they must obviously be making less mistakes than others. Hmmm.