The sub dock on Hydra station is clearly in a harbor or cove. One would not expect the sub to immediately "dive" while in a shallow area. Story construction of the action within the submarine-the-bomb-the aftermath was poor, blowing up freighter poor. As one person noted a long time ago, at least the writers are consistent with their basic medical-legal-science errors.Also, Flocke in Terminator mode cannot be killed by conventional weapons. Widmore's men should have known that, but kept firing away, being picked off like ducks at a carnival shooting gallery. Why Flocke did not change to Smokey to wipe them out is unknown, unless he wanted some target practice prior to leaving the island.
How Flocke "knows" that some candidates are still alive is also unknown. His reaction was such that he thought that the submarine would at least surface first (that's why Claire was surprised that the submarine "sunk" but in reality, subs do go underwater.) Flocke storms off the dock vowing to finish what he started; it was almost a curse that instead of moving pieces around to do his bidding, he would have to finish the game himself.
And that huffing gets back to the weak plot line that the whole Lost experience was merely a game between supernatural beings, and the main characters merely toys, pawns or red shirts. In the game of backgammon, the whole purpose is to "remove" your own pieces (characters) from the board (island) as fast as you can after getting them into the "home" position.
