Checkpoint A. Enter the building, and go through the vent. Drop down to find a 
  bag.
  Checkpoint C. Climb up the pipes after the area with three heavily armored 
  guards. Jump upwards, then across to the next building directly in front of 
  you. This building has two red cranes on top of it. A bag is to the left, next 
  to a chain fence.
  Checkpoint D. You will eventually escape onto a crane. Jump down to a landing 
  mat near a second crane. Jump to the ladder of the second crane from the 
  landing mat. Climb up the second ladder on that crane to find a bag.