Mazda Repair: timing or blown engine, oil drain plug, compression check

Question
my sister had just had her oil changed and she ran out of oil because the oil drain plug came out the car didn't get hot she went maybe two miles but now it turns over fast like no compression my guess is it jumped timing when the resistance from low oil on the cam it might have jumped timing the timing belt hasn't been changed and it has 150000 miles on it and when it turns over fast i don't hear anything detonating it has a 1.6 so it shouldn't have bent the valves i was just wondering if my theory was correct about timing or does it soundlike the motor is blown also the cam is turning so i know the belt isn't broken but i think it may have jumped

Answer
What model Mazda?

No oil is a killer and death comes fast when run dry on OHC engines.  You'll have to perform a compression check to test your theory as a no oil situation can cause overlapping issues.  Sounds to me like excess ring to wall run out.