Rogers eyeballed Gaetz having a chitchat with McCarthy, and apparently saw Gaetz mouth the word "committee." It's unclear exactly what the 2 were talking about, but Gaetz was serving on the House Armed Services Committee, which Rogers chairs. It apparently looked like McCarthy and Gaetz reached some sort of agreement.
We're guessing -- but seems like a good guess -- Rogers was worried McCarthy was going to give the chairmanship to Gaetz in return for his vote, and that set Rogers off.
C-SPAN got shots of Rogers losing it, walking to the row in which Gaetz was sitting and then fully lunging at him. Other reps tried to thwart an attack by grabbing Rogers by the chin and shoulders ... holding him back.