May doesn't enjoy spending her days in a cubicle. She knows she could quit, leave this line of work. Go fly planes for a commercial airline or something. She doesn't want to. She took a beating, and not just a physical one, that day they started calling her The Cavalry, but she's not weak. She hurts, but Melinda May doesn't fall to pieces.
Instead, she staples files. Turns down offer after offer to join this team or consult on that mission. One idiot accuses her of hiding from her past. She doesn't say anything. She doesn't need to explain herself. She knows what she needs. She's not hiding. She's healing. She heals enough that when the time Phil Coulson comes to her cubicle telling her that he only wants her to fly his plane (as if), she says yes. She doesn't feel ready to get back into it. But she knows herself. She can do this now.
