Quite literally a "splash" shot, I think it was the fact that he got it to check to leave it so close to the pin as he probably wouldn't have been able to judge the lie that well
Agree that the execution wasn't too difficult but getting the control and distance was pretty good in the circumstances. I also agree that he got luck and it was a 1 in 100 chance that it stopped as it did. Still you have to take the chances when they come.
As Imurg said he was lucky it didn't go in further and as a result had a chance at a shot to nothing - I can imagine he was thinking well lets give it a go because if I don't then Mahan's got two putts for the win.