Ryan knew he should have kept quiet, but if he had, then he wouldn't have told the siblings that he knew who was attacking them. He couldn't have let them know involuntarily that he was paying for a mistake. That they were all paying for a mistake he had committed when he was eighteen.
Regular teens made mistakes like staying out late or doing drugs, but Ryan, his mistake had been to tear apart a family that hadn't done anything.
He was the cause of the pain.
The person who could have saved them, but he didn't. Instead, he wanted to save Jill alone. He didn't care whether the rest of the family died.
He had known the meeting from the start. He had known that the accident could take place, and maybe he thought that warning Jill when they were about to be crushed would win him love, but that only earned him permanent hate.