Im stuck, on the bit where you have to climb accross under the bridge, on "highway 17", when you get to the otherside, there is a gunship that you have to shootdown, and then im not sure what to do, because, i can see up onto the bridge but cant access it, the room i am in is the one with the control panel, that says bridge inaccessable, and its flashing red, when i go back down the stairs more combine have appeared but im unsure of what to do next?? been stuck on this bit for days now, please someone help, im sure you dont need a screenie, because, i have described it quite well!