"Make one sound and I'll shoot," says Desmond, shoving Locke and telling him again to move.
Kate hustles as fast as her elbows and knees will take her, making her way to a vent overlooking the room of obsolete machinery room, where she can see Jack looking around. She shouts his name a couple of times, but Kate's got a long way to go before her lungs can compete with Mama Cass.
The rest of this we saw last week, with Jack about to press a button on the computer, Locke coming in to say he shouldn't do that, and then Desmond pointing his gun and then Jack taunting Locke and then Jack recognizing Desmond. (This time, though, when Desmond fires his warning shot, we see that it almost hits Kate.)
Back on the raftlet, Sawyer and Michael are still glaring out into the blackness. Sawyer sees a larger piece of raft, one with its own pontoon. Presumably he's looking for his own place again, so he gets down on his stomach on the edge of the raftlet and starts paddling with his one good arm, without saying anything to Michael, who looks over to see what he's doing, and sees the pontoon portion himself. He tells Sawyer to stop paddling, since that'll put a strain on the bindings, which will break up the raftlet. I'd buy that, considering that splashing Sawyer's other raftlet was enough to destroy it. Sawyer ignores him, and sure enough, his portion of the raftlet collapses, so Sawyer's treading water again. Shark's-eye cam checks out Sawyer's butt. Michael offers his hand to Sawyer and tells him to climb up, but Sawyer says, "I do and we both sink," so I guess the fight's over, but Sawyer still manages to sound like kind of a dick saying it. He says he's going for the pontoon. Underwater-cam, and we see the shark glide by. And yep, there's a Dharma logo on its tail. You have to freeze-frame it, otherwise you'll miss it. That's the kind of touch I like from this show. You'll find it if you're looking for it (but it doesn't really matter if you miss it), and it'll add something to your enjoyment, a reward for close watching. "Don't be an idiot," says Michael. Yeah, no kidding. The island already has plenty of those. Before he goes, Sawyer hands over his gun and tells Michael that if he sees that "toothy son-of-a-bitch" to aim and squeeze.
Then he starts splashing his way over to the raft, screaming like the baby of Monica Seles and Maria Sharapova, if such a thing were biologically possible. At Dharma, we're working on it! Shark's-eye-cam gets closer and closer to Sawyer, until finally they bust out the phony shark dorsal fin to break the surface of the water. Michael fiddles with the gun, then starts shooting, and to improve his aim and his terminal deadliness, starts screaming. "AAAAAAAHHHHH!" he screams. One of his shots finds the target, as evidenced by the red splash of water, and just like that, the bio-shark or cyborg shark or whatever the fuck stops. My own experience with sharks is minimal, definitely, but this one seems like kind of a puss. Especially if it's a guard shark. But now there's no sign of Sawyer, so Michael starts yelling, and then he gets down on his stomach and starts paddling over, which I guess he knows how to do in the special secret way to keep the raftlet from falling apart, like it did when Sawyer did it. He gets over to the pontoon portion, which is when Sawyer hauls himself up on the other side, and then he grabs Michael's hand and helps get him onto the new, improved raft (now with pontoon). It's nice that they're friends again. Surviving shark attacks will do that.
Final flashback of the episode. Michael waits on a park bench for Susan, who shows up with an impossibly cute Walt, looking about, I don't know, two? Three? Four? She apologizes for being late, since packing's "been a disaster" and the plane leaves first thing in the morning. Michael's unsure what to say, so he shows Walt the stuffed polar bear he brought for him. Funny how being attacked by a polar bear a while ago didn't make Michael think of this.