When the Eighth Doctor appeared to have died in the middle of negotiations with the Ice Warriors, she ordered Gregson Grenville to activate the atmospheric re-ioniser and fry the tourist shuttle the Ice Warriors were on. This failed when Professor Boston Schooner had sabotaged the emitters allowing the Ice Warriors to breach the base.
Following this, Finch announced to everyone inside to evacuate into the passenger rocket to Mars. She refused to wait for the Doctor, who had survived, Gregson and Tamsin Drew and ordered an immediate take off. When the Doctor and Tamsin made it with Gregson's remote detonator at the last moment, Finch refused to open the doors to the landing bay. Finch tried threatening the life of Tamsin so that the Doctor could activate the detonator, but he refused. (AUDIO: Deimos)
Afterwards, the rocket was pulled back to Deimos by an artificial gravity eddy. After forcing the Doctor to repair the base's atmospheric re-ioniser, the Ice Warriors killed all 600 people on board the rocket with it — including Finch — while testing to see if the Doctor had meddled with the device. (AUDIO: The Resurrection of Mars)