First of all, does a marine player need permission to use pods in Cities of Death?
No
Now assuming that the drop pod is placed in the street between buildings, but scatters to land in the ruin, what happens? Ruins are described as dangerous terrain for vehicles, not impassible. So the pod could theoretically land there, but would it have to make a dangerous terrain roll? If so, how fast does it count as having moved? Also, what if it isn't possible to position the pod model in the ruin?
The current arguement for Drop Pods is that their set-up is really "deployment' not "movement", so you answer your question with the question, can I deploy in ruins and what happens?