@surfer – your argument is specious. In the real world, we are never in this situation. It only ever happens in fiction (e.g. “24”).
In the real world, if you start down the slippery road of torturing people “only when you’re sure it’s OK”, you pretty quickly get into a rotten state.
What do you think the reaction of the friends and family of the people you torture will be? Won’t they want to seek revenge?
What effect will it have on the torturers themselves? Will they end up becoming increasingly confused about where the line lies and whether they’ve crossed it?
What do you think other people in other parts of the world will make of it? Won’t they follow our example, but with fewer constraints. They’ll just get on and torture whoever they fancy. And we won’t be able to condemn them.
In reality, you won’t ever save any lives in these situations, but you *will* start down a road to a place that is very hard to get back from.