The Taliban doesn't send people tasty lunches. Roast beef is not a pathogen. Cookies are not enemy action. There is no risk in letting me set some of this on a table somewhere.
Obviously, they don't agree.
Eventually, as I begin to set things down on the floor and call my restaurant to see what's up, a third dour looking woman in scrubs opens the door. I begin to consider the fact that the reason they won't let me in is because it's a cloning facility for dour looking women.
She doesn't say a word, but beckons me with a crook of her finger. I follow her into the lobby, through a side door, and down a hallway that seems longer than the building should allow. I hope she's not leading me to my death for uncovering their cloning scheme - or, even worse, to some kind of love shack.
Context wishes to know who sent you.