Im actually trying to see if I can get to the Didect at the end using these methods. It's hard because you need to launch 2 boxes down the front ramp in the final area, then take one out back and launch over the loadzone, move 1 crate off the main ramp to one of the side platforms, use the 2nd crate to launch BACK over. Go back into the resupply room and barely out the front door to the main area. Initiate Cortana talking, checkpoint and objective marier on main plat. Go back out back, launch over the building again. Avoid landing on main plat. Land on side plat that your box is on. Launch to didect.
It works because going over the building lets you retain low-gravity in the final area. The resupply room resets your gravity to normal. But for some reason, low-gravity doesn't kick in on co-op at all.....