No comment to make on this incident.
But remember reading in the recent past (might have been a post on Pprune) a comment from a pilot who had done many landings on slippery runways in large transport a/c. His advice was always bring the a/c to a complete halt on the runway before proceeding further. He adamant that if all a/c did this we wouldn't see the slide off at the end incidents as a/c vacate the runway.
Of course, we might not be too popular with ATC and following a/c if we did this on a regular basis.