They have decided to save the power, meening the person Hudspith choose keeps Immunity. In the game so far there is..
1 Hidden Immunity Idol with one person in Tambaqui Tribe.
1 Hidden Immunity Idol with one person in Jaburu Tribe.
1 person in Jaburu tribe with the power to Steal Immunity.
This is the person that Hudspith choose's last Immunity of the whole game.
Unicorn has immunity.