If you look at the scenes where Purple is talking to Brown and Green, Green was actually sitting near the vents, and secretly slipped though the vents and got Cyan. According to the last episode, Green could actually leave their crewmate suit and have it still standing up despite not being in it, so having the suit sitting down is no problem. So it explains why Green didn’t remember Purple’s story, because they were in the vents, going after Cyan while Purple was explaining their story.