Mk7 1.6 Tdci Engine Revs Went Hyper

[bryfly]

Hi guys wondered if anybody had this problem before, driving along suddenly notice a warm / hot smell in the cabin for a few seconds, then the revs of the engine went really high,(lost drive i think) quickly turned engine off, restarted and everything was fine, no warning lights came on, thought it might have been air con gone wrong but tried it and it is working fine, or could it be a dodgy Turbo. any body had a similar expierence??