Killed everything in the same room with Shiro, and nothing. We had Danika and Nika helping from the start-selection..
Only thing different is, I think, is that the Elementalist boss earlier wasn't killed, ran past it to the Danika's cutscene. Mission objectives thenagain, don't state you have to kill every boss, only reach Shiro and the Emperor...
Sending a report to ANet anyways :P