Yes, the road is very narrow and this is not what one would consider a safe drag race despite the road being empty. Obviously if one is to drag race it should be done at a dedicated drag strip offering greater width, safety barriers, and safety crews.
The 991 Turbo S is stated as being 377 pounds heavier than the McLaren MP4-12C. Additionally, on paper it is rated at 64 less horsepower. On that same paper this should be an easy win for the McLaren. Paper does not race though, cars do.
The launch of both cars is somewhat odd. They seem to be babied out of the hole and then they get on it once moving. No revs are heard before they "launch." Was launch control used? It does not look like it. It also appears to be a very short race without the McLaren getting a chance to stretch its legs.
Does this video really show the capability of both of these cars in a drag race? Not really. Narrow road, no launch control, short run favoring all wheel drive, etc. Come to your own conclusion.