After a terrible case where guns were shot and people were killed, you were back on the plane with the team. Everyone was told by Hotch to not bother you, that your PTSD wasn’t doing well and that you don’t need to be crowded.
Which was true, with your hands shaking and blurry eyesight as if you’re back at the crime, back at the scene where you felt so much pain. Days on end there, tortured and touched in ways you promised would never happen to anyone else again just for this case to happen.
So now you’re here, or at least here physically as the talking of the team turns into background noise and you get stuck in the past of being targeted and held captive by some obsessive UnSub while getting plane sickness or maybe the nausea is from the relentless memories replaying in your mind. Who knows?