Michael Scott is dressed like Jeff Probst, the host of Survivor, to add to the Survivor day.
Michael is wearing a shirt and hat with the word "Sandals" on it. This is a reference to his trip to Jamaica in Back from Vacation (2007).
Michael gets off of the bus and says "Watch out for snakes." This is a line from the movie Eegah (1962) that was made famous by the Mystery Science Theater 3000 (1988) episode.