Toba...

Note the operative term "almost." If you were too close or in an otherwise vulnerable location, yes, you were terminated. If your food supply went away due to the rapidly changed climate, and you couldn't come up with a suitable substitute, you were terminated. Organized civilization, confronted with a disaster at that scale, would certainly be terminated (these days, throwing a few nukes around just to ice the cake). But the species as a whole, however diminished, survived. Otherwise, we wouldn't be here talking about it...