Wouldn't some of our special ops guys (sharp-shooters) equipped with Barrett .50's and stat-of-the-art scopes, knowing where Zawahiri is be able to pick him off at about 1/2 mile out? Perhaps, Mullah Omar with him if they're out in the open discussing stratagies...
More like 5+ km.
Of course the danger is that it would be a mortal wound, not a quick, clean kill.
But a W-88 sends a big, clear message, doesn’t it?...