Luigis

I don't know if this idea has already been posted, but I thought of something when I was looking at the subtitles for S2Ep7. Martin Summers wanted Alex to get involved in Operation Rose because he thought uncovering it would help to get Alex home, right? But in Alex's idea of her world, 'you can't change history, things still happen as they were going to happen', which we've seen from the fact that Alex couldn't stop her parents from being killed.
I don't know if this next part is going to make sense, but what if uncovering Operation Rose kept her from going home? What if it only made things worse? Before Alex knew what Summers was really after, she said that he was the reason she wasn't going home, that he was the infection. But when Alex seemed to beat the infection by the end of ep8 and helped Summers uncover Operation Rose, she had a false wake-up.

Could changing the course of history be keeping Alex from going home?

its an interesting theory! i mean both sam and alex thought saving there parents from splitting up or not dying would send them hom and that was changing the course of history but it didnt