Mary is a character mentioned in Fallout 4.
Mary was a scientist working at the Cambridge Polymer Labs. She and the other scientists were locked inside the labs by Jon Elwood-Woolum when the bombs fell. When she tried to get the U-238 from the isotope containment, she was locked in there by Wil Bergman.
Mary may be the Glowing One encountered in the Isotope Containment. According to Ericka's terminal she was locked in there, and according to the Isotope Containment terminal there was a radioactive leak. The combination seems to support this claim. She could alternatively be the scientist' skeleton found in the location.
Mary is mentioned only in Fallout 4.