Neither one thing nor the otherpan-Hindu
The story turns entirely on a loophole. Hiranyakashipu could not be killed by man or beast, indoors or out, by day or night, on the ground or above it. Narasimha is neither man nor lion, appears on a threshold at twilight, and holds him on his lap. Every condition is met and none is broken, which is why the story is told as an argument rather than a battle.