Yeah, that's absolute bollocks and here's what the rules state on who can unlap themselves:
"This will only apply to cars that were lapped at the time they crossed the Line at the end of the lap during which they crossed the first Safety Car line for the second time after the safety car was deployed.
Having overtaken the cars on the lead lap and the safety car these cars should then proceed around the track at an appropriate speed, without overtaking, and make every effort to take up position at the back of the line of cars behind the safety car. Whilst they are overtaking, and in order to ensure this may be carried out safely, the cars on the lead lap must always stay on the racing line unless deviating from it is unavoidable. Unless the clerk of the course considers the presence of the safety car is still necessary, once the last lapped car has passed the leader the safety car will return to the pits at the end of the following lap."
So all cars that have been lapped when the safety car has crossed the first safety car line on its second lap, can un-lap themselves. Not one, two or three, all cars that meet that criteria.
Once the last lapped car (not the third, fourth or fifth) has passed the leader the safety car will pull in at the end of the next lap.
i can't see how it can be anything other than an open and shut case against the FIA?
MInd you, they invented a new version of the rules for the Belgium farce when it came to racing laps behind the safety car, claiming that the in lap was also a racing lap even though the lead car never crossed the finish line for a third time before the race was red flagged.