There is a class of effects known as Body Modifiers, these describe things like having a broken arm and the effects of such on battle or other actions. When I asked about Brilliant Key hitting Solar Radiance I was hoping that it would result in Solar picking up a Body Modifier of "things are broken" to slow down our opponent.
These wouldn't normally be useful against the Hyper Evolved Snake because Shed Skin removes all body modifiers at the end of its turn.
Since Hard to Kill stops Auto-Kill, and it's ludicrous to think that Red Rose can give her attacks a Times-Hundred-Million multiplier, I expected Red Rose can make Body Modifiers she inflicts stick. If she can, then hitting each head with the "Head is dead from impalement" Body Modifier would eventually leave the Snake with no living heads and render it dead by induction. Since it's not a damage effect it can't be healed by Solar's attacks, and it assumes Red Rose just says no to regeneration effects as a potent ability.
The problem in this view is that each head needs an attack action each to apply the damage and modifier. Actions that she would be running short on because of all the attack negation flying around.
But it was said not to take that long, so the preceding can't be a description of what actually happens/happened.