I rode for the Sheriff’s Department for 5 1/2 years early 70’s to late 70’s. The only serious injury I took during that time was a 4 inch kitchen knife in my left lung from a young lady about her size. She was sweet enough to do that while I was on the ground trying to put the cuffs on the husband who had just beat the chit out of her. He did 2 months in County she did 16 months in State. I did a few days in the hospital. Had I seen her coming I would have shot her in a heartbeat.
I don't know what happened in that station office in Texas.
But your story is very convincing, the quick damage a knife can do to anyone, cop or not.