Walter,
Given the Political situation, as well as the Terrorist threat, at that time; I agree that any aircraft Captain with such a Passenger list would wish to depart NI airspace with the greatest dispatch, coupled with the minimum exposure to potential hostile action. I know of no person who has suggested otherwise. Given the Wx conditions at Aldergrove that evening a high speed low level departure was totally appropriate. Whether it was appropriate to continue with that course of action as they approached the fog enshrouded Mull is another matter.