If this theory is a spoiler, it means I'm an awesome guesser because the last episode I watched before I wrote this is s01e06.
Anyway, my guess is that the green-haired girl(Yoooouuuuu, my green-haired girl...I remember when, we used to sing.) intentionally erased everyone's memories because she liked at least part of the crew and wanted everyone to get a new start. She erased her own as well so that she wouldn't act guilty around them.
Alternatively, you can look at the people she encountered in the memory while she was hiding in the vents and realize she is definitely not either of those two dudes during the memory, which helps if my guess is wrong. I'm horrible with names, and I only remember one dude for sure, the one who almost spaced her, or whoever she was remembering from.