In my opinion 1 hour isn't enough to really portray the amount of time that is passing. Les made it work with Survivorman and 7 days of survival, but 21 days is a long time... and it seems to be compressed down to arguing, complaining, and then success. It feels like it could have been 5-6 days.

On the Island episode they were so eager to start they definitely made a mistake setting out across the water right away (and with no improvised extra flotation?). In hindsight I imagine they would have been better off waiting till first light, so they could avoid the extreme sunburn.