Re: If
Russia clammed up on the gas composition until quite recently. As you point out, this probably cost a number of lives by making ER personnel guess at the medical problem.
It goes without saying that if one is using a weapon like gas on civilians, it is the responsibility of the police/army to have on hand some form of treatment or antidote to deal with problems afterwards. Hell, they should be carrying a supply of antidote just in case of accidents to their own people.
While the end result is still better than 600 people killed by terrorists, this could have been handled a lot better.