Black Castle, the underground laboratory.
As Angel opened his eyes, what came into view was the pure white expanse of the laboratory beneath the light source overhead, which was slightly dazzling.
Angel stretched out his fingers and pinched them together.
The firm sensation of making a fist allowed him to confirm that his consciousness had returned from that ethereal cage to his real body.
Angel turned his head, just in time to see the "Gate" gradually fading away.
With the return of his consciousness, the "Gate" that connected both sides would also dissipate.
Angel checked the Gate Model on his Witchcraft Slot and found that the special energy previously covering it had shrunk to a point.
Just as he had speculated earlier, to enter that strange passage again, he would have to wait for the special energy to fully Diffuse again.