1.5 seconds, while moving, from concealment is FAST. The fastest I can draw reliably (A-Zone hit, 7 yards) is right at 1.0-1.2 seconds, and that's from a Ghost holster (USPSA rig), no concealment. We drill regularly on draws, focusing on getting good hits. But like I said, that's under the best possible circumstances.
If you can draw and shoot in 1-2 seconds in any circumstance, that's fast. Most people are surprised at how long it takes to draw and fire accurately when you're using a shot timer, even when you know that it's coming. Add surprise, reaction time, disorientation, adrenaline, etc., and you're going to have to rely on ingrained instinct. 1-2 seconds? Hmmm...