Ulla Vax was a Special Agent of the Anti-Dalek Force.
Vax disappeared while on a mission to Palk. Later, her body was found frozen in ice in the Arctic region of Gra 2. According to a report by Mark Seven, her death was apparently caused by multiple electric blasts consistent with that of a Dalek execution squad.
Among the belongings found on her body was a standard issue ADF micro recorder. The recordings found on the device were partially-inaudible, but told of her investigation of intense Dalek activity by inflitration of the slave workforce, which required the digging of wholes four miles deep in the ice for some sort of nuclear device. What she had found out appeared to be a Dalek mission to throw several planets in the Seventh Galaxy out of orbit.
Making her way to an engine, Vax had been fired at by a Dalek, which wounded her in the leg, however she managed to escape with a particle of Crystallanium (although this was not found on her body), an important part of the guidance system on the engines.
The last part of the recording indicated that she had climbed in an ice bucket to escape and that there were some Daleks in the vicinity. (PROSE: Special Report)