Giant fuckfest, knocking things off the table, it's all very athletic on every surface of the house and yet also very sweet and hesitant, the way they're banging the shit out of each other. Steve's finger gets caught in a silverware drawer and Fiona doesn't even notice, it's pretty awesome, but just before she comes somebody starts banging on the door. They both scramble around and she runs up the stairs to get clothes or something, so Steve has to answer the door -- after a faceplant or two struggling into his jeans -- with his shirt still off.
It's the cops, which is weird for Steve especially, so he runs up to find Fiona, running into a wild Liam on the Loose, Debbie running to catch him, on the way. "Yeah, uh, cops? Looking for you?" She doesn't even have time for the weirded-outness of Steve at this time, and just heads downstairs. Where the cops have brought Frank home, like every night, with soiled pants and a deadly complexion. They dump him on the floor and the cop, Tony, looks at Fiona a little wetly, maybe because of Steve's shirtlessness. Everybody loves Fiona; Steve is clearly hot enough that "everybody" should be worried.
Does she usually leave her father on the floor like that? Yeah, every night. Always gone by morning. And then who was the black toddler running around upstairs? Which is really two questions, one of which has bearing on the situation between them, but both of which have the same answer: "Liam? Liam's my brother." And we won't be discussing it any further, if you really think about it.
It's a friendly, sort of sad goodbye that happens next. Drunk dad on the floor, cops all around. He thinks it's a situation, he doesn't understand that it happens every night, even though it's clear it does. Steve's got a lot of things to consider right now, and needs to leave; Fiona, on the other hand, assumes that Steve's Ghetto Tourism trip has come to its logical end. She nods to herself: This is what you get for trying.
When Steve gets to the car he looks back at the window, hoping to see her -- hoping to turn back around and up the steps -- but it's just the rest of the kids, staring down from a window. He salutes, and leaves. Fiona goes to bed lonelier than before she met Steve.