Checkpoint A. When the level begins, you will reach a rooftop with a lot of 
  ventilation fans. Opposite this area is a building with a large "Duel" sign. A 
  bag is to the right of the bottom of the "Duel" sign.
  Checkpoint C. Drop down from the elevator after it crashes in the shaft. A 
  guard will open a door. Run towards the wall, then climb up and over to find a 
  bag nearby.
  Checkpoint D. Run down the subway stairs, and navigate the platforms. Jump 
  onto the tracks at the end on the right, and go up the ladder. Carefully swing 
  on the bars, and do not fall off. Wall Run Jump onto the furthest bar, then 
  swing onto the ledge. You will see the Mirror's Edge logo on the wall and two 
  bars. Jump up onto one of the bars, then turn and jump up to the ledge that 
  has a bag.