Realising that Earth's atmosphere must be poisonous to the aliens, Quatermass sabotages their life support system, pumping oxygen into the large domes. Simultaneously, Quatermass' assistant, Brand (William Franklyn), sacrifices his life by launching a Quatermass rocket at an asteroid believed to be the invasion's staging point. The individual aliens combine their small bodies to create huge 150-foot tall creatures that soon burst from the domes. The rocket destroys the asteroid with a nuclear explosion. Their base gone and now fully exposed to Earth's atmosphere, the giant masses of combined creatures collapse and die. The V-shaped marks disappear from those affected, leaving them with no memory of having been under alien control. As they head back to the village, Lomax wonders aloud how he'll make a believable report on all that's happened. More pointedly, Quatermass questions just how "final" will that report be ...