My first thought when the Private recognized the serial number of the Green Rooster was that he had a buddy on the chopper. But I do like the theory that they were on the lookout for the serial number for some reason or another. Deserters, disguised spec ops unit, a group of scientists, who knows? Also Leedo yeah the suppressed MP5 is suspicious. There is no good reason for coast guard chopper pilots or the coast at all to have suppressed weapons for standard operations. If I remember correctly, California is one of many states where suppressors are illegal. So where the hell did that come from?

I think we need to question why the the bodies were left behind. I believe the hospital is the new arena, so the Z's have somewhere to bring the corpses to. But according to Scratch in the after the credits scene, most of the zombies ran off after the tower collapsed. But that was several hours ago. To me it seems that there was a good chunk of time for the zombies to come back and collect. Also they didn't even take Steven and crew from the car, who I thought were torn up by zombies. Was I wrong in how I interpreted that scene in chapter 24? Are the zombies up to something else? Is there some other secret about them? Is it as simple that they were scared off by the tower collapse and the Mallers searching the area in force? I am trying to come up with a reason but I can't. Maybe it is like the early chapters where the zombies took a few days to collect the dead. Maybe they are comfortable right now, thus not desperate to gather food. If they are comfortable then things are going their way...
Last theory on this is that maybe the biters take longer to come and collect when there is a large number of bodies...but they cleaned up the arena explosion relatively quickly...