A second hit on the mitochondria

Later work found it does not stop at the outer membrane. It also reaches mitochondrial membranes and disrupts them, which removes the cell's energy supply at the same time as its outer boundary fails. Two membrane systems failing together is why the effect is fast and why the cell cannot repair its way out. It also means a cancer cell's usual escape routes, which are mostly ways of refusing to undergo apoptosis, do not apply.