Yes and I think that the could not take a sniper shot due to the glass window, if it did get him the hostages would have been in danger of the gunman shooting them.
With the benefit of hindsight you can find thing you could have done or done differently but at the time you just deal with it to the best of your ability.
Should have Abbott spoken to him as he was demanding, don't know but it would not have made matters worse IMO