Got cold due to sleeping in bikini > tearfuly told her boyfriend she can't go > boyfriend opted to not go as well and promised her family he would take care of her when they go to guam = living under the same roof for a few days arc..... probably...
mild cold-> everyone overreacts -> ryou comes over -> omoi overreacts and plays out dying spouse delusion -> ryou shrugs it off and takes care of her normally
ah the dreaded japanese cold.
or maybe we'll be lucky and get a plot twist where she's been kicked off the flight after trying to get on the plane early and being found in the overhead pleasuring herself to his pictures.