I thought all that mattered was what happened in that exact moment for a self-defence claim?if KR pointed his firearm at Rosenbaum unprovoked, then Rosenbaum was following him to warn of an "active shooter" (or other lawful reason).
But defense has introduced multiple sources who say Rosenbaum threatened to kill KR if he found him alone, earlier in the evening. So Rosenbaum was chasing KR to execute on an actionable threat.