They are definitely aware of the speed.
We've all seen plenty of reaction videos for rides in fast cars. Of course, a lot of those videos feature passengers of the busty variety, and are often a bit exaggerated. But this is something slightly different. For starters, there are a lot of different passengers, so you get a wide range of reactions, although it's safe to say that pretty much everybody was impressed. Another cool thing about this video is that the McLaren P1 is actually being driven on a track, while many others aren't.
That said, sorry about the lack of boobs, we miss them too.