It doesn't matter if it causes an interference, the rule requires that he take complete relief. The only time that partial relief is allowed is in a bunker when it is not possible to take complete relief without moving closer to the hole.
In my opinion, he did not take complete relief. He should have dropped 4 or 5 inches farther back from the spot where he actually played the shot.
played Weds, for the first time all summer :( and shot a 55 over 9 holes... and could of been better but the last couple of holes i just went durrrrrrrrr with several 8's,,, if i could ever cut down my 3 putts, i'd be shooting low 40's consistently...
It clearly is the same water in the larger puddle.
The next question would be if his weight combined with turning his foot through the shot caused the ground under his feet to move and allowed the water to backflow to where his foot was