the tattoo as the signature of intoxicated irrevocability
the chilling thing about the intoxication is that it seems to make you consider only the adrenaline of the moment itself, not (in any depth) the irrevocability that produces the adrenaline.
Context
Ewell's tattoo obsession resolves into a small theory of the whole disease: the intoxicated impulse fixes on the adrenaline of the moment and cannot project past it to the permanent consequence that is the very source of the thrill. The tattoo is addiction's signature act — the buzz of an irrevocable decision made by a mind that has been chemically prevented from imagining the irrevocable part.