Drilling into the centre of the Earth, causing global seismic earthquakes and volcanic eruptions that destroy the planet is undoubtedly one of the biggest mistakes ever committed in Doctor Who. Professor Stahlman's attempts to drill into the earth to obtain unlimited energy has such dire consequences, he doesn't just threaten this world, he almost destroys the Earth in two realities. Stahlman is one of those bosses who will not listen to reason. In both realities he forces the Inferno project to keep drilling even though those actions release a primordial ooze, an ooze that transforms him into a deranged Primord. Not even the Doctor can convince him to stop. He destroys the Earth in one reality and almost rips it apart in another. Thankfully the Doctor was able to save his reality and kill the transformed Stahlman with a fire extinguisher. The next time your boss makes ridiculous demands of you, you know what weapon to use!