Towards the end of the film, Alex and Clear seperate, as Alex realizes he's next. After seeing a picture of of Christa and Blade, however, he comes to the realization "I never moved!"
Now, in his vision, he did move and Billy (Sean William Scott) barely makes it on the plane in time. But since Alex didn't move and that changes the order, then apparently we're going by where everybody was located before the 7 got off. The problem is that outside the vision Billy never got on the plane. He was caught in the fight and pushed off. So, there are two choices.
1. Go by vision. Clear dies, then Alex.
2. Go by reality. Alex dies, then Clear: Billy lives.
Unfortunately it seems we're choosing between both because Billy was killed off, but Alex was set to die before Clear.