Hmmm, I noticed another mechanic while on auto-pilot: If there are excess moves from a dice roll, they can be used on other unfinished lanes, e.g. Runner A is 3 empty panels away from the end while Runner B is 1 away, Nazupon rolls a 4 and the game picks Runner A, which leaves an extra move for Runner B to finish in the same roll. Pretty neat.

If it's been there the whole time, I must have missed it.