Great analysis.

One thing it made me ponder as for the potential sequence of events. As peeps have suggested Shannon's visions of Walt might leak to AL and lead her to believe Shannon is crazy/the others/etc.

Given Walt's 'abilities', what if he tells Shannon something wicked scary about AL? Shannon confronts AL, or AL overhears something, and the stuff hits the fan. Walt might have seen AL after the capture. Maybe AL is a mole to get inside the group again (after all, Ethan seemed to have a purpose as a spy and they can't get another one in there unless they believed them to be a crash survivor.)

The main reason I think this is because of the emphasis on BE in Kristen's quote...might actually BE a monster. This hints of some sort of Others/island influence which again singles out AL as the only possible female culprit.

I just hope the next 'vision' isn't scrambled and backward.