Let's get it out of the way first: BMW is letting the computer have all the fun here. The Bavarians have taken drifting, one of the most enjoyable things a person can do with a BMW M235i, and given it to a computer. This is sad.
On the other hand, it's research that all the other automakers should be doing. If autonomous cars are coming, and they are, they need to be able to react to emergencies. Often, reacting to emergencies involves controlling a car beyond the limit of traction, and that's exactly what this is.
Unfortunately, BMW didn't bother to send us a video of the self-drifting car, so we can't show you what this looks like in action, but we have reached out to BMW and demanded said video.
UPDATE: BMW responded, and we all know what a self-drifting car looks like in action now.