I can think of someone who fits all the criteria(military code, Iron helmet, "you wouldn't believe me if I told you" which implies it's someone he knows, possibly more powerful than the flash.)
Another possibility would be Doctor fate, given the helmet. Khalid Ben-Hassin was "hired by the military to find Nabu's tomb", so he may have knowledge of military code. And would you believe it if someone told you "I captured an all powerful Wizard"?
Or who knows. Maybe wade eiling becomes the general on earth two. Explains the code, the not believing it (This a-hole you once knew is actually the hulk), although not the helmet
One more thing. Zolomon was zoom in the comics. Who's to say that earth one zolomon isn't zoom, and the man who is trapped is Jay Garrick. Yes yes, the whole "Hunter Zolomon Serial Killer" thing. Okay, now I'm really stretching things, but couldn't it be that Zolomon, perhaps, comes from earth two? And perhaps Jay from earth one? I don't know, the whole "playing the hero" and "hope" thing didn't sound legitimate to me.
So what are your theories?