But if the overtaking starts on Lap 56, even if it is towards the end of the lap, even though all lapped cars haven't overtaken cars on the lead lap, wouldn't the safety car still be pitting the following lap if it ended on Lap 57? That part I'm unclear about. In any case, I think the race director can be say the 'safety car is ending this lap' at any point, which is I think what the stewards argued (14.13). I just think it'd be less controversial if they'd unlap them all even if they couldn't join back up with the field.
Yeah, I guess you're right. He did seem quite keen getting the safety car in, and said later it was based on the agreement between teams about wanting to end races in the 'green' conditions. Still think they could've unlapped cars a bit earlier, which would make it less controversial (possibly). Problem would be whether all of them would get far enough in front for it not to matter.