I think that it will depend on how and why it came off. For example, is there a broken bolt in the crankshaft? Did the car overheat while the pulley was off? I doubt that the timing would change as long as the chain tensioner was good to begin with.
Well, the steaming is not good. Remember that once the pump stops, the coolant circulation stops also, so you are no longer reading the temperature inside the engine. I would not want to run an engine for 5 minutes without coolant circulation. It is a good thing that your coolant did not blow.... The overflow tank cap did not pop out but the bottle was steaming a bit. The engine was run for less than 5 mins total after the pulley flew off. Temps never reached above 220 F from my readings with my code reader...