The smoke monster kills Whitfield & other officers but spares Richard

The Black Rock is sitting in the jungle during the day. Richard and Ignacio wake up and hear the officers above. One says that Captain Hanso is dead. They call up to the deck for help and Jonas Whitfield comes down.

Instead of helping them, Whitfield kills three of the surviving slaves, including Ignacio. He says that only five officers have survived and they have limited supplies and fresh water. As he's about to kill Richard, Whitfield says that if he doesn't kill him, it'll only be a matter of time before Richard kills him.

Suddenly, we hear the familiar sound of the smoke monster, who ravages the officers on deck. In burst through the ship and grabs Whitfield before slowly sliding back into the ship. It creeps up to Richard and does it's little flashing snapshots, much like it did to Juliet in the season 3 episode "Left Behind." When Richard opens his eyes, he finds that the smoke monster has silently disappeared.

So why at this point does the smoke monster kill everyone but Richard, but in the future, it seems to let a lot more people live? Is it because Jacob's plan and the rules involved have yet to completely evolve, or was Richard specially selected by Jacob for a purpose?