LOL. Even Calhoun can't believe how daft you are.
The argument to be made would be that the company's policies encouraged acts of violence or didn't do enough to prevent them. If lucky enough to overcome the burden of proof to establish either (which wouldn't happen), you're still stuck with the fact THAT HE WAS JUSTIFIED AND WHAT HE DID WAS LEGAL. They aren't going to be found at fault for an act that the legal system has already declared was legal.
You are venturing into a level of legal stupidity that ranks right up there with the sovereign citizen idiocy.