Umpire Interference Question

[SAZBA]

No one on. No one out. Batter hits ground ball to left side of infield, BU thinking batted ball got through to left field, runs into the infield to pivot to see BR touch first.

Just then the ball whizzes by the BU's head because the ball was actually fielded by third baseman deep in the hole. Umpire, as cool as the other side of the pillow, makes the "out" call at first. BR out by a few steps.

First baseman is wide eyed looking at the umpire because the BU almost got nailed in the back of the head.

I'm not going to lie. That BU was me. I seen both the third baseman and short stop go for it but I swear the ball got through.

I know about a batted ball hitting an umpire but what about a thrown ball like in this situation. Live ball, play on? If so, what if the umpire is knocked out?