You know that panicky feeling when you’re trapped somewhere and a bomb is about to go off? No? Neither did I until last night at 6 p.m., when security officials evacuated the downtown bus tunnel. I was waiting for a light rail train at the Pioneer Square station when a woman in an orange vest started waving us out. She said she didn’t know what was going on, but she was in a hurry and there was a flashing yellow light and so naturally we all got out of there pronto. There was nobody outside directing us or giving us information, so I walked to the International District station, also closed, where several King County Sherriff cars were parked. The officers there wouldn’t give out any information either, but a nearby Seattle Police officer directing traffic suggested maybe there was a bomb scare.Nope. King County Metro spokesperson Linda Thielke says that a water alarm had gone off accidentally, and that it took about 45 minutes to resolve. She adds that the trains continued running south of the Stadium station, something we could have found out if we subscribed to Metro’s transit alerts. Hmm, I wonder how many people do. A woman on her way out of the Pioneer Square station said she was going to catch a taxi.