Red Sox/Yankees Question

[rulesmaven]

They showed a highlight on sportscenter this morning with ambient audio, and you can hear the PU verbalize on the point "that's a strike," and then "safe" on the plate play signal.

I thought perhaps the reason for the slightly more exagerated strike call than usual might have been that the batter abandoned the box when he saw the runner coming and maybe the PU initially thought the batter was going to attempt to call time late or something. Also the pitcher altered his delivery a bit when he saw what was happening, and maybe the pu was running through whether the almost-quick-pitch was a balk as the pitch was on the way, and so put a bit extra on strike call to emphasize no balk. Lip reading during the game, the pitcher seemed to ask the PU after the play whether a balk had been called, which seemed unusual. Maybe he was asking "ball"?, but it looked like "balk?"