As the group walk through the cave after leaving the bodies, they walk along a concrete path with concrete steps. Concrete would not have occurred naturally and there is no reason for anyone to build a concrete walkway in a cave in another dimension.
Zed goes to talk to his brother, and there is concern that he won't listen, so Wren comes along. In the initial scene, his brother attacks and Zed seems to fear for his life. But Zed has the kinj of control, and could easily command him to get off, to help, or whatever else they desire.