The Dread that was following Dean didn't have the most well-developed mind of that cave. It wasn't the most cunning nor strongest Dread. However, it was one of the types of animals that were sharing a place in that cave for a very long time.
Their specimen was able to do the most important thing to any animal: reproduce quickly, evolve, and survive for as much time as possible and continue reproducing.
Due to this fact, that Dread knew very well those tunnels. It wasn't knowledge at all, but an instinct. Walk across those tunnels was just as natural for it as breathing. Ever since its birth, and until its death, it would be familiarized with each square millimeter of that cave.
That's why it could get a shortcut and intercept Dean.
Yes... only intercept.
