I think he knew Kamui's goal or at least a part of it, but his own was a separate one. Of course that was also made possible by Kamui, but they were allies, so why not. That shop was for people getting those drugs which turn people into zombies, so it wasn't a random place they chose. All the people present, save the Inspector and possibly employees, were the same kind of zombie people he was. I'm not sure if he foresaw all of them getting slaughtered, but perhaps he did. It would then be like a suicide bombing to send a message, even if the message was lost on the specific people he was "treating" on site. But then again, many of those died anyway receiving his treatment, so it's questionable if they were the intended ultimate audience. All in all he was a bit too passionate to have done all that to only incite Aoyanagi.