Hello, new here. I was bored before the airing of the show, so I was watching some past episodes of Doctor Who. Luckily, The God Complex was one of them. That being said, the Doctor states that the first ghost (the one with the beard) is an alien from the planet Tivoli, which is the same race Gibbis belongs to from The God Complex. He says it when they are all together in the Faraday cage.
Now, why would a Tivoli, a race who wants to be conquered want to leave their planet, and what could he possibly be hauling? I mean, the craft was small, and since he was the only ghost, it only makes sense that he was the only crew member. Also, and this is the big one, who wrote the words in the first place? Did he, and then he died somehow? Or did someone else, and then they killed him? If the first is true, then clearly it was some sort of distress call, and he was hoping to be rescued possibly. If the second is true, well, then there is something far more sinister afoot.