The dispute between Abbott and Raynor on this seems like a classic example of speaking at cross-purposes. I think Abbott would accept that, if it's clear or at least highly probable that a given person is about to commit a terrorist attack that will cost many lives, then the police should intervene with deadly force in order to prevent this. If that's the only way to stop an imminent threat, then it's necessary. On the other hand, if there are alternatives to deadly force that would just as well stop the threat -- for example, because they can arrest the suspect before they reach their target -- then those should clearly be preferred.
It's pretty obvious that Raynor meant the first case, ie police shouldn't be prevented from using deadly force when necessary, but held to strict standards on what counts as necessary; and it seems equally obvious that Abbott's criticism is based on a misreading of Raynor's point.