Pretty much .
He had the knives in his hands so he was a threat and that is how they will get off...
Yes having knives in hand ready to slice and dice IS A threat... but at the point they opened fire he was a strategic threat not a tactical threat.
By Strategic Threat I mean one that takes longer term ( not in the next millisecond) planing and preparation for .
By Tactical Threat I mean one that requires immediate action.