This was pretty bad to witness, as the Cassowary was racing around the exhibit and chasing the Emu and Rhea into the corners. As you can see, there was hardly any space to escape the wrath of the Cassowary, with lemurs looking down from above.
I worked with emus for a short while, and we lost one due to the results of stress. And there wasn't even a cassowary involved.
This is gonna end badly, but I guess the zoo might not care much about losing an animal every once in a while.