Nicholas Briggs (in-universe)

A man with a beard who voiced Daleks worked in the Dalek Dome. He was killed by Georgy Gold when she was hypnotised by the Dalek simulacra.

Behind the scenes
Though not stated to be such, the man can be clearly seen to be Nicholas Briggs, a prolific real-world voice actor who has portrayed the voice of the Daleks for both Big Finish Productions and the revival series of Doctor Who.