Having distorted space inside a dimensional tunnel wouldn't typically force the experts to worry about their surroundings. However, Divine Demon had already confirmed the species of the pack in charge of that environment, and Noah knew something about those magical beasts.
The Space Hounds were unusual creatures. Very few records kept track of their existence. Noah had learnt about them inside the libraries of the Sailbrird family. Still, he had guessed the rest of their features through his expertise.
The areas of distorted space completed the puzzle about his idea of those magical beasts. It became clear that the Space Hounds could walk freely through the edges of the dimensions, and that led to a scary conclusion.
Those magical beasts could already be around the group. Noah had no way of confirming the presence of that threat from inside the dimensional tunnel, but he could guess that some scout had already noticed their arrival.