When Duanmu Huai returned to the Tribunal, he also appeared utterly exhausted.
Dealing with Ghouls and Vampires wasn't a big problem, but the appearance of the Son of the Black Goat brought significant tangible losses to the Tribunal. Not only did the strategy team suffer heavy losses, but the Night Guards that Duanmu Huai brought with him also lost more than a dozen people. It is important to note that the Night Guards are soul carriers and have no physical bodies. Yet, even so, they could still be parasitized by the Son of the Black Goat, which just goes to show how terrifying Shabu Nicolas is...
This reaffirmed Duanmu Huai's determination not to casually bring anyone to that world again.
If the Night Guards could be infected, he did not want to test whether the Soul Cards would receive the same treatment.
