they're just waiting for us to enter Baghdad... if they launched from Baghdad while our troops were in the streets, they could be fairly certain that we wouldn't use any nuclear or otherwise massive ordinace in retaliation...
then, if they launched the chemical weapons towards our supply chain or HQ, they could profit from any resulting confusion in fighting us in the city...
or heck, if he's feeling maliciously suicidal, Saddam could just release an agent IN Baghdad... wait until we've "seized the objective", after we think we're through with the worst of the street fighting, when our forces are fully concentrated in Baghdad... then, SUPRISE, here's all of those Chemical Weapons, detonated right under our noses.
eesh, nasty business.
may this find you well,