Dead Rising/Saint

In order to acquire the Saint achievement, Frank must rescue at least 50 survivors in a single playthrough of 72 Hour Mode.

The most survivors possible Frank can save is 53 of the 54 survivors. Frank can never save all 54. Either Dr. Barnaby or Simone Ravendark must die.

This is one of the most challenging of the achievements. However, in order to get 50, you must fail some of the cases in the game. There are only 47 survivors that you can rescue in the mall. The other survivors must be Brad, Frank, Otis, Jessie, Ed and Dr. Barnaby. To save them, you must fail case 6-1, then finish all other scoops. If you complete the cases, certain fates await Brad, Jessie, Dr. Barnaby and Ed, so fail case 6-1 to get "Saint". With that in mind, it does mean you can miss three survivors in the tight schedule and still complete the achievement. To have Dr. Barnaby live, do not meet with Isabella after fighting her or avoid the fight completely and let the story end there.

You can also fail the cases 8-1 or 8-2 and get the Saint achievement as well.