On the one hand, if I were the pharmacist, I'd have probably opted for carrying, as well.
On the other hand, the pharmacist signed an employment contract, knowing the rule was in place. He's probably out of luck with Walgreen's, and may have a hard time finding employment anywhere else as a pharmacist, unless he opens his own business.
It doesn't seem like lawsuits going after employers who post such rules, yet fail to provide security, have had much success. Maybe this should be another project for SAF.