@spider “you can’t do heat scans under the earth”
I’m not all that scientific, so I may be flawed in my reasoning but my thinking is this: Once the corpses have been cyber-pollenated, the organic material would regain some semblance of heat, thus making it possible to detect via infrared (or something like that)
On a different note, a friend and I were theorizing about how the Doctor had tried to disprove the existence of Robin Hood, and how he should also eventually disprove the existence of Santa Claus. Lo and behold, who should appear in the closing credits?
So it seems like the Doctor lied to Clara about finding Gallifrey, but did he really? Missy gave the coordinates to the Doctor, saying it had returned to its original place. Doctor goes and looks and gets upset when he doesn’t see it. However, Missy had said “different dimension, yes. Lost, no”. So maybe the Doctor was looking at the right coordinates, but wrong dimension.