I don't think he'd walk out, I mean he's getting a title match. He should consider himself lucky to even get a title shot because of all the rumors surrounding Mcmahon not liking him and not seeing him as a main event guy. Or maybe he was supposed to lose the match that's why he walked out idk.
They wouldn't have him win the #1 contender's match if he wasn't supposed to compete in it.
It's probably an injury... again, a wellness policy violation , or by a small chance the IC title match is going to be on Wrestlemania. But I doubt it since Big E and Christian are in the battle royal at WM.
Christian should at least get one last run with any individual title then retire IMO, he's getting burnt out and injury prone already. As much as I want to see him main event, I think his body can't take it anymore. Physique wise, he's looking very scrawny.