Tested this in a skirmish match 5 minutes ago.
Simply use a Winter Veil Disguise Kit any time before the water pushback comes along, when it does, you are stunned so it shouldn't push you down.
Wait a few seconds since there's more than 1 push back i belive then dispell the buff and voila.
Can't really get you a picture.. yay a person standing in the pipe? Just give it a try.