I mean, what’s the worst that could happen?  Paralysis??

Say ‘Dad’ one more time!  I dare you, boy!  And I know that we don’t have much to go on in the way of relative size or perspective, but Rusty’s legs are indistinguishable from Mark’s as they go into the water…

Good thing that Mark seems to have natural buoyancy.  All Rusty has to do is grab him by the hair and drag him to shore!!