Lost Series 5 episode 11 Whatever happened happened

Night. Jungle. Darkness. Jin slowly comes to and hears his walkie squawking: the hostile has escaped! Jin radios in that he was just attacked and the hostile is heading north. Then Jin hears young Ben struggling to breathe and finds him lying in a heap in the road... shot and bleeding.

At the barracks, the fire from the flaming van and house are now out. Horace thinks the hostile used the fire as a diversion to escape. Jack points out that if he was locked up, how could he start the fire. Horace says he had help, someone who let him out of his cell. And since there wasn't any other hostile crossing the perimeter, that means it was one of them.