Who Ya Gonna Call?

From Asia Times:

"Russia's unprecedented joint war games with China can be viewed as a dual message to the United States and the Central Asian republics of the extent to which Beijing and Moscow are prepared to go to protect their interests."

I might find it a little worrisome if it weren't for this news (U.S. Help Enroute to Russian Sub). I notice the Russians didn't call on the Chinese for their help. I wonder why?