I don't think potential terrorists should be interrogated near death because of assumption. If they were innocent and just falsely accused, they have to go through such traumatic experiences. If they're adament on their innocence, they should be taken into consideration until it's proven otherwise. I'm sure there are more techniques that are less drastic, I mean... punching or something could provoke a confession, but holding someone's head under water until they almost drown isn't ideal. You may accidentally kill them and then NEVER get a lead in your investigation.
The government can take extreme measures in times of threat, but it should only be when they KNOW of an actual terror cell and not "Oh, we're going to generalize and MAYBE you are apart of this organization, let's tie you up to horses limb by limb and have them run off in different directions."