2nd level: Kills all infected units.
3rd level: Kills a selected infected unit.
It doesn't seem like it would make the skill too overpowered. Instead, it would gain the ability to earn a bonus for additional infection on both NDs, not just the second one.
Знание некоторых закономерностей освобождает от изучения многих фактов.
Мечты сбываются рано или поздно, так или иначе.