There was no doubt that Monica and the others were worried about his sudden announcement of departure, especially considering Luke had yet to recover completely from his last battle.
However, none of them allowed their true feelings to show on their faces. They understood that trying to dissuade him might accomplish little, so they chose to support him in whatever way they could, even if it meant swallowing their own concerns.
Monica, in particular, seemed unusually eager to help him prepare for the journey.
She busied herself with packing his belongings and preparing all sorts of things he might need along the way, barely giving herself a moment to rest.
To anyone else, it might have appeared that she was simply being a thoughtful lover, determined to ensure he had everything necessary for the trip. Luke, however, knew her too well to be fooled by the act.
