Important to note - all of that criticism was constructive, and all of the questions were exactly the sort of questions you HAVE to answer to have a tight script. It's amazing how much work goes on beneath the surface; frankly dialogue is the easiest part. If dialogue was all you needed, you'd be writing for the radio, as David Mamet famously suggested. (He comes across as an utter asshole, but he is sometimes [but not always] right.) So I got raked over the coals on what was weak, what was too lose, what didn't serve the tightest possible structure.
In the past, I worried that the group's feedback was all positive. I went home feeling kind of bruised and grumpy, but after I slept on it, I realized it was incredibly useful and constructive; it hurts the way a Drill Sergeant's physical training hurts - it makes you stronger if you can gut it out. I can definitely gut it out, and unlike past writer's group, I know this criticism is coming from a very positive intention, of being helpful, of hammering the story into shape, of doing the hard work.
So much like the day after a hard workout, when one is sore but feels virtuous, I feel like I got the kind of savaging I needed, the kind that says I can't screw this up, that I have to pay attention to every nuance and every detail, and to above all be very honest.