|The following is based on Creation Club content and has not been confirmed by canon sources.|
Listen to the "faint radio signal" to be directed to the Fens Way station. Make your way there to a door to the subway maintenance access. Enter through a Novice locked door, and through one of two arched doors in the wall to find what appears to be an abandoned camp. Clear this section of the metro tube and continue back right to be ambushed by a feral ghoul who crawls out behind some scaffolding ramps and another feral who appears to be sleeping on a bed.
What remains of Wally Mack, who is now a glowing one, comes down from the top of the scaffolding ramps. Kill him and collect some interesting loot.
This article is too short to provide more than rudimentary information about the subject. You can help Nukapedia by expanding it.