Maybe Lucy's a little bit of both. Eagle Squad Training is hellish; it kills people. It has prepared us all, physically and mentally, for whatever task there is we need to do. So when we need to leave no survivors, no one walks away that isn't part of the Enclave. Practiced hands make for short work. And there was much work to be done that day.

As for what Venom did, as far as we know he really did just miss one. I doubt he'll get too much flack for it.