In a prior episode, Dogen told Jack that Sayid had been "claimed" by a darkness that would corrupt him when it entered his heart. He would become not the man he used to know. The darkness is the perceived evil. That is the reason Sayid was initially "banished" from the temple.
If Dogen knew Sayid is evil, why give him a job to do, or why let him back into the temple? Especially in a "lock down" situation. The only reason I can fathom is that he wanted to be killed (to transform?) Remember, ghost Jacob was doing something at the spring when Hurley walked in pre-mission . . . maybe reversing the infected spring to create his own zombie army of Dogen and Lennon.
It was telling that the knife into Flocke came out with no blood. There are no traits of a human body just the mere illusion of one. It infers that there are multiple Flockes (one with Sawyer in the cave, and one at the temple) The most important clue on the night was when Dogen said Flocke/MIB was "evil incarnate," which means an evil deity or spirit embodied in flesh (human form).
This is more confirmation that the Island of spirits. What the Island represents is still vague. If MIB is to believed, he is trapped on the island like a prisoner who wants to go home. The term "banished" has a meaning here, too. In a theological context, the "evil incarnate" is Satan, who always wanted to build an evil army of demons to go and take back heaven.
There appears to be a growing number of "claimed" characters: Sayid, who has gone into full dark mode; Claire, who has been in dark jungle mode for years; and Kate, whose confused look leaving the temple was a clue that she did not survive the pit (as Claire had vowed to kill her for raising Aaron) so at the very least Kate is "infected" by the evil spirit on the way to full metal zombie. Sawyer was "recruited" and not "claimed," and according to the ghost boy to Flocke, he cannot be killed. TPTB need to clear up this rule book of what spirits can and cannot do on the Island.
