He and Thélash were hired by Prefect Zevron to retrieve Miranda Dawkins from 20th century Earth. When they discovered the Eighth Doctor was there, they wanted to leave since they were aware of his reputation.
Whilst talking with the Doctor, Rum slipped a mini-nuke into his pocket so he could kill the Time Lord if necessary. Unfortunately, the Doctor later took his coat off in their saucer and left it there. When Rum detonated the bomb, it destroyed them instead. (PROSE: Father Time, COMIC: Miranda)