That's not as near a close call as it appears. The zoom lens compresses depth of field to make it appear they're on top of each other, but the aircraft that went around hadn't reached the threshold yet, and the aircraft that crossed was almost a mile from the threshold. Worth a go around certainly, but not "split second reaction saves terrified passengers from certain doom" material. It's a dramatic seeming video, suitable for short attention span viewers during a 30 second spot on the evening news to hold viewers over the commercial break. Meh.
Interesting. From my first time viewing this I doubted its authenticity. I thought it was maybe a little more realistic than the very funny short video of the DC 10 landing on the 405, but still a fake. But my impression came from exactly what you're talking about here, compression of the depth of field. I just didn't recognize it.