It is a bit early to tell, but I feel like this series has gotten closer to finding its stride ever since Shuli was added. Having a Shin-like character who knows nothing makes it much easier for mangaka to introduce the characters, the world, and the stakes at hand every single time.
The characters have been the highlight of this series so far. It feels like there is potential for them to become more than the typical Shōnen Jump protagonists. Although they do still feel sort of manufactured like many Shōnen Jump characters (Haiji's laugh felt kind of awkward to me every time), there is an organic element to them – for lack of a better way to put it – that just makes them very charming. I think this was on full display this chapter.
I just have to hope that none of this potential is squandered by either the mangaka or Jump's editorial team. I think Under Doctor has built the most solid foundation out of all three new series; it just needs to find its stride now.