Calamity questions (spoilers)

[Alomentis]

Hello, brand new to the site, but not to the cosmere or multiverse. I just finished calamity today and I've got a couple questions. Actually just one. 

Near the end of calamity, david asks himself how prof knew their location. Then later obliteration appears and says he cannot travel anywhere he has not seen, and david asks how he could possibly know his location underground. There is, as far as I know, no resolution to this! My thoughts were that knighthawk somehow had betrayed them, but it just completely gets ignored! To be honest, I feel calamity had a very rushed ending which is not normal for sanderson. Did i miss something? Anyone else have this question?

[Kheran]

Hello, welcome to the forum

I think it's pretty simple : Obliteration just needs to think of someone to teleport directly to him. David just showed him a picture of Calamity and Obliteration was able to teleport there, without knowing the place. And yeah, I agree, it felt rushed toward the end, which is a bummer

[Embrisk he/him]

The ending felt crazy rushed, except for the chase scene with prof. That felt unnecessarily drawn out.