Did no one else catch (presumably Arnold's) voice telling her to kill him? It would follow that the voice overrides their programming, allowing or compelling them to do things not normally permitted - Dolores and the gun, the Stray and the rock, the massacre in the bar.

Well, I'll be using that all the damn time, now.

But… Deckard pretty clearly *is* a replicant. I'd be interested to hear how else you interpret Gaff and the oragami unicorn.