in FED rules, from the windup, he can only deliver a pitch or legally disengage by stepping back with his pivot foot
from 6-1-1 art 2
With his feet in the wind-up position, the pitcher may only deliver a pitch or step backward off the pitcher's plate with his pivot foot first. After the pitcher has placed his pivot foot clearly behind the plate, he has the right to change to the set position or throw or feint to a base the same as that of any infielder. During delivery, he may lift his non-pivot foot in a step forward, a step sideways, or in a step backward and a step forward, but he shall not otherwise lift either foot.
The run does not count because the third out of the inning was the result of a force out - even though he tagged the runner and not the base, it is still a force out
th3's post in Weird pitcher move was marked as the answer