Prod. 2519 - The Rescuers (XVII) - Seq. 06.1 - Part "B" - Organ Chase
Animation of Crocs and Mice mainly by Frank Thomas, with five scenes by Ron Clements and two Medusa scenes by Milt Kahl.
With Frank being the supervising animator, he most likely planned each shot, then handed out some action scenes to Ron Clements.
My guess is that Frank had fun planning and animating this!