Hit-by-Pitch or Swinging Strike?

 
With a 1-1 count, the batter (B1) turns to the pitcher and squares to bunt. The pitch is in the middle of the batter's box and hits B1 in the stomach. B1's bat remained over the plate during the entire pitch and even while he was being struck by the pitch.
 
The defensive coach insists that B1's actions with his bat constitute a strike and B1 should remain at the plate with a 1-2 count. What should the umpire do now?
 
Call
Even when the batter is struck by the pitch, if the batter strikes at the pitch or if the pitch is in the strike zone, a strike is added to the count and the batter remains at bat. In the situation below, the pitch was not in the strike zone, nor did B1 strike at the pitch, so B1 is awarded first base. The position of the bat during the pitch is not a factor.