ouch that sucks. I'd refill the radiator with water and water and water wetter and drive it around. If everything feels normal (no excessive or out of the norm smoke), just as "smooth", just as "powerful", I'd probably just leave it that way.
Do check for oil in the coolant after that.
I think you should also check if the cooling system is still pressurized overnight. (If I'm not wrong that means it's bad...)
oh well.. sorry to hear that. I hope everything works out fine!
maybe if you posted this in the Diesel forum you'd get more reply!
oh and welcome to mercedesshop!
2008 BMW 335i Coupe