The boys had to do an escape room game, and one of the hints was for the locks in the room. The hint asked Wanna One to come interview NU'EST along with Eric Nam at the book cafe in Seochon. The boys, after staring at the hint for a bit, realized that it was supposed to be directions. The 'seo' in 'Seochon' is the Korean word for 'west', 'book' in 'book cafe' is the Korean word for 'north', and 'nam' in Eric Nam's name is the Korean word for south. The boys couldn't find east, but Minhyun posted out that was actually in NU'EST's name.
Although the 'cameo' was just a mentioning of the name, it was still a cute mention especially because Minhyun figured out the NU'EST clue.
You can check out the moment below.