The story on that is that the Chinese sub, a diesel electric, had been absolutely tagged, bracketed, and was forced to surface.
The Russians learned a very valuable lesson from an encounter very much like this one. In 1984 the USS Kitty Hawk carrier group drove a Russian sub to surface, problem was they surfaced in front of the Hawk (oops). The Chicoms should learn in a carrier vs. sub collision, the sub looses big time.