I have done some research on this subject and have concluded;
Damn the state law! Bottom line is they are still bound by federal law and it's illegal to possess, manufacture, distribute, grow or use marijuana by federal statutes. Some cities have said they will attempt to prosecute under federal law. Have to wait to see how that plays out.
You use the example if they shot someone; Good shoot/bad shoot will be determined by the courts but the other issue may come into play; so even if their marijuana license is legal by state law, they were in possession of a firearm while committing a felony (growing/using marijuana).
As we all say... anything can happen but do you want to be the test case in an already confusing state law vs. federal law?
I would give this some very deep thought before doing it.