Coach's Interference?

[Armadillo_Blue]

R2. B1 drives a ball into the outfield. R2 rounds third as the ball is on its way into home, clearly well in front of the runner. The third base coach, out of the box (if that matters to anyone), raises both hands in a stop signal, and steps directly in front of R2's path. R2 slams on the breaks and stops just before colliding with the coach and then trots back to 3rd. It is obvious that the only reason R2 stopped was because he had to to avoid the collision, however there is no actual contact.

Does this constitute physcially assisting the runner in returning to the base, and is thus an out, or is it nothing becuase the runner managed to stop in time?