This would explain a lot.
Biden clearly knew that Trump would soon be “challenged’ in a way like never before. We know that because he gave that to George Stephanopoulos as the reason for him to not exit the race.
Biden’s handlers knew he couldn’t be trusted to keep a secret and likely would not have told him if there was a plot to assassinate Trump.
But Jill was telling Biden not to exit and she most likely needed to give him a reason.
Cheadle was her friend, put in that position by her specific recommendation.
Means, motive, opportunity.