If not evil, why do you limit it to (you assume, though the question is rarely ajudicated) terrorists? Why not on drug dealers or car thieves or shoplifters? Why not (its being not evil, after all) on your own children?
Then, being a Catholic, you could go to Mass immediately afterwards and present yourself for Holy Communion.
Because it is a measure to be used to extract information from recalcitrant individuals, information that could prevent mass killings.
While the illegal distribution of narcotics, the theft of cars and the boosting of merchandise are all very distressing, they do not automatically result in the consequences to human life that, say, a explosive backpack on the London Underground or the hijacking of a terrorist aircraft does.
Quite simply, your other examples are not accompanied by justifiable urgency.
Why not (its being not evil, after all) on your own children?
It is not evil to shoot someone who is trying to kill you - but just because shooting someone is not an inherently evil act does not mean that I would ever want to shoot one of my children.
Pouring someone a shot of vodka is not an inherently evil act either, but I would not pour my five year old a shot of vodka, regardless.
The flaw in your reasoning is pretty obvious: not all actions have the same moral import in all circumstances. Only a very few human activities are inherently evil.
Then, being a Catholic, you could go to Mass immediately afterwards and present yourself for Holy Communion.
If I needed to inconvenience someone in order to save someone else's life, there is no reason why I shouldn't be able to assist at Mass afterwards.