Mary is a woman who was treated in the ER after the train crash.
Mary and Yvonne were traveling together when they were in a train crash. Yvonne seemed okay, but she came to the ER with Mary, who needed stitches for a cut on her forehead. After the cut was stitched, they had to wait for an x-ray to rule out internal injuries before they could leave, so Yvonne settled in next to Mary's bed to wait. Mary's scans came back with just a broken rib, so she was told she'd be given pain killers and then she could go. When Yvonne's phone rang, she appeared to be asleep. When Mary tried to rouse her, she collapsed to the floor. Despite the doctors' best efforts, she died in the ER. She'd been bleeding into her abdomen since her arrival and no one had noticed.
Yvonne and Mary are friends. They were traveling together when their train crashed.