I think the first tie breaker is win percent within the division.
Right now the Ratriots are 3 and 0 in the division with three division games left.
The Bills are 2 and 2 with two games left.
Winning out the Bills will be 13 and 4, but 4 and 2 within the division.
If the Rats lose to Bills and Ravens, they will be 13 and 4 but own the first tiebreaker.
For the Bills to win the East the Rats need to lose to the Bills and 2 other games so we have the best record. Rats lose to Bills, Ravens and Dolphins? Possible.