Mariel and Celinee spent a few hours at an inn in the northwestern part of the city—they needed rest and food after being on the move since morning. They only left the city about two hours after sunset.
Mariel and Celinee weren't the only ones heading northwest in the dark.
Some members of Sterminatore were also moving in that direction, along with a few mercenary groups. The mission given by the palace seemed to be more than just capturing the princess; there was also a mission to limit the monster's movement and ensure it didn't head toward populated areas.
Celinee had mentioned that she didn't sense any individuals classified as "strong". From this, Mariel concluded that no plan had been made to capture the princess. They were only monitoring and luring the monster to keep it within a designated area.