^Some people already mentioned it, but here it is. The licensed version just released, too, for those wanting to support that author.
I like seeing people's different take on what exactly the meaning behind this was, but I just took from it that it's one of those, "this kind of really sucks, but hey, at least I'm not completely alone" type waking up moments. Granted in this setting I'm sure there's a lot of that for both of them. Everyone points out how Acchan seems to be the most effected, but Rii also was over sleeping all curled up at the start. She's the one who brought back the alcohol. They both probably take turns coping with everything while equally trying to help each other get through it as best as possible.