From a kayfabe perspective, why would Brock wait till Friday when Baron could potentially win, and then he'd have to try to cash in on a fresh Baron vs a battered Seth?
He could've won the title tonight, but then he'd have to face a fresh Baron Corbin on Friday. If he waits until Friday, he'll either fight an absolute dead Rollins or a fatigued Corbin. Boombox Brock playing kayfabe chess