A strange sleeping arrangement with his mother - check. A creepy devotion to dead things - check. Incapability of accepting that Bradley will never love him - check. This all sounds like the Norman Bates that will grow up to commit the atrocities in Psycho, and Bates Motel has slowly been adding the eerie character elements throughout the season without the need to have Norman kill anything. Well, sort of, since he kind of has.
Norman's been going through some troubles though, and the pressure his mom is putting on him about surviving with the new motel can't be helping. He just saw a stray dog he led into the road get run over, he's lost the girl of his dreams who claims that whatever happened between them needs to be like it never happened at all, and his brother is getting super heavy in the drug trade. All of this along with the regular things in life that a boy his age must face, like the clingy crush Emma has on him. Obviously it's not easy to cope, but Norman has always had a problem with that as we learned a couple of episodes back.
Norma's not doing so well either, since her motel is slowly sinking under the weight of the various crimes that have been committed there. No one wants to be associated with a murder house, except maybe the man in room number 9 of course, and the motel isn't attracting much business because it's off the main route. She's also dealing with Norman's altercations, which are now causing the school to notice and request him to attend some counseling.
"Underwater" also explores the Bates' inability to leave town. They'll lose all of their investment if they walk away from the motel, and yet they're in a bit of a pickle because of all the threats they receive. Things aren't looking good financially, which could be a partial motivation for Norman and Norma later in the show - if the motel isn't drawing in customers, they'll have to find other sources of money.
Bates Motel has overall been an enjoyable experience, and I'm pleasantly surprised by this. If the previous episodes of the season are any indication of what's to come on the season finale, it'll most likely be explosive and fraught with tension. Here's hoping the show leaves on a good note to come back strong for a second season.