I had one let go at full chat in 2nd gear coming off a roundabout, had I had a passanger they'd have had very badly burnt legs, it went everywhere. It even made a low pop/thump like noise when it went. I shat myself, thought I'd blown the engine up with all the (what I initially thought was) smoke.
Also when watching a trackday a few years back a MKII came tonking down the straight at Combe and suddenly steam poured out of the windows, the car dived on to the grass and the passanger jumped out and pulled his tousers off while swearing.........a lot!
Nick