Screen A
Pence was in it from the get-go. We all kind of knew, he got the letter at Bush's funeral, and is essentially a dead man walking. He could seal his fate today by going with Biden, and let the DS continue to control him. Or he choose to change history, and accept whatever consequences Trump has in store.
Screen B
Pence made his plans with RR and Trump knew right away. Bush funeral note was to give Pence an opt-out. Trump has been letting it ride, with instructions to Pence ever since. Whatever happens today is by POTUS design.