In the episode, The Lodger, what really was the monster and why was it sucking in all those people? Why werent the Doctor, Craig, and Sophie killed when they touched the electric...er...orby thingy

The machine on Craig's house was a TARDIS, or atleast a ship like a TARDIS. In the episode "The Day of the Moon", I believe it was that episode, they find Amy with the aliens that called themselves "The Silence", and they had Amy in a ship that looked just like the one on Craig's house. The doctor said he hadseen one of those b4 but it was abandoned and now he's probably goin to find out why. I think that was one of the Silence's ships that had been abandoned after they were evicted from earth by the doctor, which was one of my favorite episodes by the way. Since they had either been killed by a human, orescaped on another ship, the crew that flew the ship in question never returned to fly the ship home so the protocol that finds a new pilot a activated and that's where the holograms came from. The reason Craig and his girlfriend didn't get killed was because they didn't want to leave so the hologram didn't want them as a pilot. However, once they did touch the bulb at the end, I guess they didn't touch it long enuf for it to kill them and also Craig touched it without the ship wanting him to pilot it. He was tryin to save the Doctors life, and the whole Solar System, according to the Doctor. Anyway, I'm not an expert, and I'm not very good with words but I hope I've helped and of course this is only my personal opinion, not facts. I could be completely wrong, I just feel this is how we were meant to interpret it.