The Time Lords' time scale of Dalek activity indicated that this Dalek was taken from the 46th century front of the Dalek-Movellan War. (PROSE: Dalek Combat Training Manual) The Dalek tried to exterminate the First Doctor and Susan Foreman shortly after the pair arrived in the Death Zone.
After identifying the Doctor's first incarnation, the Dalek began chasing him and Susan through a mirrored corridor — only to be ambushed by the pair in a dead end and pushed down an alley.
The beams from the Dalek's energy weapon reflected off the mirrored walls, bouncing back and forth before striking the Dalek and destroying it. When the Dalek casing exploded, the mutant inside was exposed but quickly perished. The explosion also blew a hole in a wall, revealing to the Doctor and Susan the Tomb of Rassilon and the landscape of the Death Zone outside. (TV: The Five Doctors)
Behind the scenes
This Dalek was operated by John Scott Martin.
This Dalek was primarily depicted with a hybrid prop combined from a top half constructed for The Daleks and a bottom half constructed for The Chase. To depict the Dalek's destruction, a second prop was used; a "goon" skirt from Planet of the Daleks was placed underneath a specially constructed top half which was blown apart.