Actually, they can lose and still survive if Birmingham and Wigan lose by enough goals to push/keep their goal difference lower than that of Blackpool.
If Wigan, Blackpool and Birmingham all lose, Blackpool will need to lose by the same (or a lower) number of goals to Wigan and also will need to lose by one goal less than Birmingham. So...
Tottenham 2 - 0 Birmingham
United 1 - 0 Blackpool
Stoke 1 - 0 Wigan
...and Blackpool would survive by having a better goal difference than Wigan and having more goals scored than Birmingham..
If it ends up like this...
Tottenham 3 - 0 Birmingham
United 2 - 0 Blackpool
Stoke 1 - 0 Wigan
Blackpool would still survive on account of them scoring more goals than Wigan throughout their campaign (much like they have with Birmingham).
