I think a lesser mangaka would have had Junpei ignore the advice and then get himself in deep trouble over nerves to generate some easy tension for the reader, but the author here has already established that Junpei, rebellious as he is, has learned to trust his teachers and so it would come off as cheap. Thus we have a much, much stronger tension building scene using the ghost and all.
I'm also very impressed by page 20, with the front shot on the eyes, then the reflection on the feet, followed by a back shot. Don't quite have the vocabulary to describe why that page feels so nice to look at, but if I had to try, it's how balanced it feels, while covering his whole body in 3 different 'angles'. It's just a very creative framing.
However, I'm really not digging the pace here, it's far faster than anything prior; feels jarring.