The speed is actually faster than it looks in the pics, Quarry is a third gear ~60mph bend, and easily catches people out, especially when the track is greasy like that.
Quarry is awesome. As skeeter said, it even catches pro's out, and is renowned for being one of the trickiest corners on any UK track. I personally love it, it's such a satisfying corner when you get it right.
Camp corner catches a lot of people out too, it's a double apex and you have to ignore the first and dive for the second, but noobs to Combe naturally go for the first apex the end up having to correct and hug the corner untill the second apex.
Quarry and Camp make Castle Combe one of the best tracks in the UK IMO.