In the side mission "Hell Hath No Fury", after blowing up the dam, Handsome Jack will read out a list of the week's construction casulaties which are: Hartnell, W. Troughton, P. Pertwee, J. Baker, T.

This is a reference to the actors William Hartnell, Patrick Troughton, Jon Pertwee and Tom Baker, all of who played in respective order the character 'the Doctor' in the science fiction series Doctor Who.
Contributed by KnowledgeBase
Attachment
Attachment
 
Video