[It's a good idea, and it's another reason Leo is glad for this alliance. As cold as it sounds, having access to his counterpart's Donatello as a resource is an invaluable gain. He's yet to see the extent of this Don's experience, but other-Leo seems to have faith in him - and he's good enough to have gotten them through fifteen years of filthy New York sewers and illnesses. (That's the leader talking, clinical and businesslike. Anything more complicated is not for war room discussions.)]

[But this Leo has seen things that the other one hasn't, so for him it's natural to that second possibility into the pot.]

If there's a power source, I'd bet on it being inside the palace. There's no security on the outside. [There's an emphasis put on 'no', because there is literally none. Not a single guardsman.] If not...we might be dealing with magic.