Stranger Danger

In our quest as parents to keep our children as safe as possible we have been having a series of talks with them about the danger of "Strangers." We've talked about how most strangers are good but what to do if one tries to come up and give them anything. We've talked about who to talk to if they are in trouble, and how to stay safe in our home. These conversations might have been a bit too much for our children based on their reactions. MD, who is curious about everything, just asked question after question about strangers and wanted me to show him pictures of them. Hyrum became terrified. Every knock on the door scares him, He refuses to be alone, and labels everyone he sees as a "bad guy" We have tried to do damage control but it hasn't really worked too well as shown by this incident:

Hyrum when walking out of church sees a guy behind him.
"He's a bad guy!" he starts saying to his dad
"What?" Michael asks
"He's a bad guy! He's a stranger! He's a bad guy!"
Michael looks and sees who he is talking about
"He's not a bad guy Hyrum." Michael says trying to quiet him
"He IS a bad guy!"
Michael is trying to hurry and get the kids in the car
Hyrum, who refuses to take his eyes off the poor man yells "He's looking at me!"
Michael tries to calm him down by explaining again that all strangers are not all bad guys when MD starts singing
"Follow the stranger! Follow the stranger! Follow the stranger-He knows the way!"

Yes I feel like we messed up a bit since neither child has quite taken the message the way we meant it.