1:that's the point this post exists because there is no point to it an is a fail in map design 2:you just posted some obvious facts about it which I think most people should've figured out for them selves by now 3: this post was made October 8th 2014 you posted in this 6 months later I'd say this post is pretty well dead
i see no actual point of this air pocket under the bridge they are stuck there as soon as water is poisoned and then c4 is the only other thing that can kill them