Was the motor running (I couldn't tell on my low-resolution screen)? Certainly I couldn't hear it - but heard the splash ok!
Perhaps they had an engine failure, were attempting to reach land, decided they couldn't quite make it (clearly it was high/not flat ground where the video was taken from) and chose the lesser of two evils at the last moment... let's not be too hard on the pilot at this stage, without further info.
FP.