The dodged bullet comes from the fact that had they play occurred in the middle of the field there would have been no review to see if he stepped out of bounds. Therefore they would not have seen the hand wave that caused the play to ruled dead.
You mentioned a false start. What happened Saturday night was the equivalent of a RB running down the sideline for a 55 yard TD on an offensive play. But when the replay official made sure the RB stayed in bounds on the run they noticed an offensive lineman moving a pinky prior to the snap. So then the decided to call a penalty.
Also very interesting that they didn't penalize DeJean. It should have been a 5 yard mark off. And the conference also didn't fine Ferentz for his post game comments.