That is obviously the correct way to do it. If a perp starts waving a knife around and threatening you, jump back in the cruiser and wait till he calms down. If a passer-by happens to get stabbed, no big deal, at least the perps civil rights are still intact. The DEAD person can take consolation in that.
But now you will say that they should do something in that case. They did, he had been walking back and forth into that store, with the knife, and could have stabbed the people working there whenever he wanted. The police told him to drop the knife, he started waving it around more. Maybe they should have shot it out of his hand.
Good movie training there. Have you ever tried to handle a person with a knife? Look up some videos of how a good knife fighter can stab you six or seven times before you can make a move. A knife is just as deadly as a gun, and is actually much more painful than most bullet strikes.
I never saw a knife