Rather than hugging the wall and avoiding lamps, right after you are launched, look right, go to the lamp, and run left once your weight is absolved. Then just do what you did and trigger the bridge start, but there's an easier to climb short rock right next to the final lamp, that if you climb on, you can kill the ogre before it event sees you with a sniper because it spawns at the second to last lamp. You kill the ogre, and only thrall will come after that, and you just wait and watch the thrall scramble around like idiots until the bridge is done. Takes way less than 4 minutes.