"If you were (maybe you are) a BP agent, that chases drug smugglers, wouldn't it be reasonable to believe they might be armed?"
Possibly but that was not the scenario here nor is it what the law allows. My assumption that someone may be armed simply is not enough to begin legally firing on them. Where live, there is no telling who is packing. That would give the cops carte blanche to drop whoever they wanted. No thanks.
That wasn't what I posted. I wasn't justifying a shooting. I said that if your job was to arrest drug smugglers....people who will do whatever they can to keep from getting caught, including firing at officers in the past, would it be reasonable to believe they might be armed and that you could be killed if you let your guard down? Or would you go into a situation like that believing a drug smuggler was unarmed and harmless?