That should suffice. The walls here are so seamless that it should stand out.

[The pristine, dark tunnels of ice are one of the more beautiful and somehow unearthly places he has seen—and he has been in Mementos. It makes them almost feel like intruders and their mark stands out in the otherwise unsullied walls.]

Why not keep going and see how far we can go in the new direction? I don't know about you two but I'd like to see what else might be here, aside from slumbering beasts.