Bergman's password is a paper note in Fallout 4. Desdemona instructs the Sole Survivor to retrieve it during the quest Underground Undercover.
Location
It can be found in the Cambridge Polymer Labs, on Bergman's terminal in the laboratory section of the building on the second floor.[1] In order to access it, the quest Cambridge Polymer Labs must be completed, allowing the Sole Survivor to leave the building.
Transcript
username: TWilliams
password: Vernon!Is!An!Idiot!
