Zoro getting up would be utter shit writing. Like the medicine's side effects are supposed to be near lethal. Zoro merely surviving those side effects in of itself is a massive feat.
Hakai immobilized zoro and the medicine just temporarily postponed the effect of the damage zoro took from that attack. Now on top of what damage he took from king, he's taking double the damage he took from hakai.
Zoro is near death and he shouldn't be able to just negate that damage for some bullshit plot reason. And even if he could just negate that damage, I've yet to see a single ZKK supporting tard explain to me why Zoro is so important that this needs to happen.