If a gun is pointed at you, it is no longer a question of defending property. That person has just presented a real and credible threat to your life. If you point a gun a law enforcement and demand the departments property...you think they are going to simply comply with those demands because the departments property isn't worth dying for? Before you go on about how different it is for LEO's...just stop. We are talking about a mindset and general principles.
If you feel that defending the property of a pharmacy or WalMart is worth risking your life go for it. Your weapon is for protection of yourself, not your employers property.