Unless they shot a civilian, right? This guy weren't no civilian, okay. And there's no reason those British officers should have ANY reason to think that he was.
Why do I feel pretty secure in this? So, what would you do?
Here's the scene: You're following a guy wearing a big, bulky overcoat (hey, yeah, it's London... but it's JULY 22nd, okay). He's a known terror suspect... I'm sorry, I meant Islamic Soldier. He's heading toward the Tube. He will not respond when you order him to stop. He goes into the Tube. You're in hot pursuit.
Now, bear in mind that you're following a guy into what amounts to a cave... a guy who has a high probability of exploding with hot nails shooting out of him and stuff. You reach the train. You take him down. He's still struggling.
[Over-puntuation alert] You. shoot. him... Dead.
Well, he was soldier, right? I mean, soldiers - in uniform or mufti - are the same, right? (That's what people are saying about GITMO and the Geneva Convention and all.) And that train was loaded with civilians, right?
So, by that definition, he is an enemy soldier very likely with his finger on the trigger of a weapon that can take out oh... conservatively a 100 people or so - most of whom are "civilians".
And their fucking problem is...?