[Urbane Guerrilla]

...except this: the rifle is probably not suppressed, but is merely being fired from inside a sizeable metal box: the van. This distorts and rather muffles the shot and makes it difficult to get a fix on exactly where the shot was fired. Compound the mischief with echoes of the report and the sonic "crack" of the supersonic bullet's passage all bouncing off various concrete surfaces and you've really got a tangle of stimuli to sort out. This guy is a middling good shot with a real knack for getting away fast and subtle. No wonder he's giving us a pain.