While I do not think the following takes anything away from what can happen when you are facing a knife attack, there are a lot of doubts surrounding these pictures.
For me, they came to me pretty much as they were presented here - with no background. They were passed my way by one of the officers I have trained in ARCON. He too stated they were pictures of a cop - but he had no other "facts" than that.
Please consider the following:
THE FOLLOWING VIDEO ARE ALL VERY GRAPHIC!!!
Here's an example of neither controlling time/space, no superior weapons technology, and "luck" determining the end result more than anything:
Here's an example of not controlling time/space, only having superior weapons technology:
Here's an example of controlling time/space and having superior weapon technology on one's disposal: