An attack whistle is something that a woman might carry to call for help if she is attacked. The use of "thingy" is an incredibly informal and colloquial way of imply that she doesn't really know the proper name of what she's talking about, or can't think of it. "that thingy over there", - That thing over there, that I can't think of what it's called. The three extra cabs just happened to come, it wasn't a result f her blowing the whistle. There weren't any police because there probably weren't any around to hear the whistle. As for what happens to people in similar situations, I don't know. It's not really a standard or common situation :P