Why No One Died When a Gunman Opened Fire on the Subway

Inside the roughly 750 square feet of a subway car on Tuesday morning, a gunman unleashed a hail of bullets, firing at rush-hour commuters at close range — captive victims.

While 33 bullets were sprayed from his Glock handgun, they wounded only 10 passengers. More than a dozen other people were injured, some of them choking on smoke from the two devices the police said Frank R. James detonated before he started shooting.

As the police announced the capture of Mr. James on Wednesday, the city steadied itself after an...