McKenna

 was a leader of UNIT in 1994. He didn't know of the Seventh Doctor and had him locked up. He was prepared to spring the trap on Gregory Lord. Exploring Ship he started to act strangely, being influenced by the ship. He killed Lord but said it wasn't his fault. Elizabeth Klein had his command revoked as he was compromised by Ship. The Doctor managed to get to abort the missile strike. (AUDIO: Warlock's Cross)