I know that none of us would "accidentally" carry into an off-limits establishment, but for just a minute, let's say you did "accidentally" forget to disarm before entering. I'm mainly talking about major no-no's, like schools, government property/buildings, ect, but feel free to expound on other locations such as malls, hospitals, ect.
While you're there, a bad guy strolls in with a gun, and he/she is obviously there to cause trouble. Maybe an armed robbery. He/She is obviously very agitated, and is acting as if he/she could easily start shooting at any second.
Would you take a chance at permanently losing you HCP and/or face jail time to save the life of someone other than youself? This would require you to shoot the bad guy, of course.