Loki's reaction was no less instinctual even if it was different. Rather than lying stunned on the table, he rolled to one side and onto his feet, wrapping his real self in invisibility on the way and leaving behind a perfect illusion. (Of himself essentially stunned on the table, sitting up looking confused... good illusions were, after all, about realism.)

He could talk through it and 'be' through it, but violence would go straight through it. Pre-emptive self-defense that didn't necessarily involve knives.