Nope. First of all, the pathologist's role in the trial isn't to defend (or prosecute) anybody. She was there as an expert witness to explain, based on her examination of Nowak's body, in as much detail as she could the circumstances of his death. How many injuries he had, with what type of blade, how deep they were, and so on. In the course of doing so she described the injuries and the effect they would have had on him, including how blood passed into his chest cavity very quickly, and how quickly he died. This led her to conclude, based on her expertise (which I certainly don't have and probably none of us on this forum do) that it was too late for him to be saved, however the police had reacted when they arrived, or if an ambulance had been called.
What I'm saying is that it would therefore be impossible (based on this evidence) to convict the police officers for manslaughter. There's many reasons for that, but the most important would be that their actions did not cause his death. That's not a "defence" of them, it's a statement of what appears to be fact based on the available evidence.