Cant believe that there would be collusion at this level at this stage of a tourney.
It just looks like proper donkey play.
The raiser has no idea of opponents stack size or pot odds. He"s just playing his hand and his stack, realises he is beaten, so folds.
He hasn"t really got enough chips to be in a position to chip dump profitably either.
Two questions for you
1. Did you look to see if they were from the same town/country (not that that matters too much)
2. Can you turn "caps lock" off