I think they screwed up a bunch of great opportunities with poor writing for the episode.

The Orchid station gets glossed over in a few short minutes after the big lead up months ago when the producers "leaked" the orientation film for it. It really seems like the writing has gone downhill since season 2. The past few finales, they seem in such a hurry to entirely write off any loose ends and start over from scratch.

The "dead man's switch" on the guy's arm -- Kearney knew nothing about the flight 815 survivors who were ferrying back and forth from the island, so the only people who would be injured by his bomb would be the ship's crew (whom he had already demonstrated that he considered disposable). If he was going to wear such a thing, why did it even have to be real? Nobody on the island could previously see the boat anyways (or hear it blow up) to know it was real.