Mr. Ripley, according to the film, the torpedoes weren't old training torps.
They are a new, sophisticated High-speed underwater ASW rocket.
Apparantly, up for sale to the Chinese, as well.
I could see why Intel services would be interested in seeing such a weapon test-fired. It will change submarine warfare quite a bit. As to the suspected collision, and an American sub torpedoeing a Russian craft in response, seem pure Hypothesizing on the part of the film's makers. That would have been an act of war, That I'm sure the Kremlin would have made lot's of noise over.