Looks like Huma is giving one of those volleyball or tennis doubles signs to the doc. Wonder what it means.
That signal means Humma needs to change her Depends™.
First thing that jumps out at me is the contrast between an SS agent and a... whatever that dude is. The SS dude is tall and athletic young man, the whateverhisjobis dude is overweight and older.
He be in charge, though, especially if one views the video that still was taken from one can tell that he's navigating Hillary into the hallway she's facing, and he's working with Huma, who as you point out might be giving him a hand signal of some kind, which might have something to do with Hillary's movement, etc, or maybe something else.
Meanwhile the SS dude is standing there ready as always, but in deference to the mystery man and Huma.
So Huma is the main handler, who seems to signal to the mystery man what the plan is, who flashes the flashlight to lead Hillary here or there... oh and by the way he's wired into the SS communications and he carries an autoinjector around with him too? Or is it a flashlight only and no autoinjector? Not enough information to rule out the autoinjector theory from the one pitcha of Hillary and all her peeps walking down the well-lit hallway, IMO.
Does he carry a weapon too like the SS? No? How would anyone know that right now? And really who is he? Is he an american citizen or is he a citizen of Tanzania or Kenya or wherever? What security clearance does he have? Is he going to be around for the debates? Just axin...