Yarborg,
In response to your original post:
It is a shame that it took such an incident to enlighten your sense of danger in your community. But, it is a good thing that you did not continue on blindly following a belief of "it couldn't happen to me."
To give a bit of an idea of law...we are granted the ability to engage in force against anyone who is inflicting unwarranted harm against another or against someone you believe may be about to commit unwarranted harm against you or another...to defend yourself or come to the aid of another who is in danger basically. So, should a person choose to engage the assailant, it would be within the law, but it may not be the best choice, in my opinion.
Should a person decide to engage the offender, I will warn you: Just be sure who you are engaging. Your wife saw what led up to the situation, so this is a bit different. But, if you walked into the store and saw the guy pointing a gun at the pregnant woman...what is to say the pregnant woman wasn't robbing the store and another CCW holder came to stop the robbery? You can not always paint a stereotypical picture against an incident, though many times it does appear to be a no-brainer, and many times it is. But there is a certain percentage of misinterpretation that can take place.
Now, to answer your question...were I in your wife's shoes, my children would have been my first priority. I would have taken them back into the dentist's office and told him to lock the door behind me after briefly telling him what was going on. I would then take my children to the farthest corner away from where the incident was taking place. I would make no effort to engage the assailant whatsoever. If the dentist refused to lock the door, I would take the children out the back and run the opposite direction with them in front of me. But, I am pretty sure he would comply given the situation. Call the police. If I had a CCW, I would try to hide my children in a closet, telling them to get onto the ground and remain silent. Even if I didn't have a CCW, I would try to do that. I would take a non-line-of-fire position between them and the entrance to the dentist's office and be ready if he were to enter. You basically want to create a triangle between your children, the assailant and you. If the person comes into the office where you are, it should be your perogative to distract the assailants attention from the direction of the children. If you can not get the children into a hidden location, I would have them lay on the floor and position myself in front of them. Definitely keep them and yourself away from windows.
Now, if I didn't have children with me...I may react differently.
You have to take past instances into account. Some robberies of strip mall-type stores result in the assailant robbing more than one of those stores. They may quickly work their way down, getting in 3 stores before leaving.
You definitely don't want to go out in the parking lot where the offenders car is located. Not only may he shoot you, but the store owner of the place he was just in may come out shooting at the assailant. You or your kids may find yourself in the line of fire, either between the 2 shooting or behind one or the other.
If you can avoid going out anywhere in the open, that is good.
The best short-term defense against a single or a few armed attackers is to barricade yourself and create a defensive position.
This is all written out and seems like a long process. But, it would be my immediate reaction and would take as little as 10 seconds to follow through with.