Do have any ideas/thoughts on stevonnies vision of the crumbling road and scary Kevin face?
I do actually!
I think that this is what happens as a fusion is too overcome with a certain emotion. Recall that in Coach Steven, Pearl told Garnet and Amethyst that they were losing themselves. This is the case here.
It starts with having literal tunnel vision. And it’s a good way to present what’s happening. Steven and Connie were so upset about Kevin that they couldn’t think of anything else. They were consumed by wanting to beat him at his own game. That’s why all the scenery disappears and all they can see is the road and his car.
And then, they start to destabilise, in the same way the Road behind them is destabilising. They’re coming undone because Stevonnie is experiencing a lot of emotional turmoil from their components. Steven with tunnel vision, and Connie, who at this point is realising that they shouldn’t be doing this. That’s why it’s Connie later who brings up what they’re doing and what they’ve become: Consumed.
But that doesn’t mean Connie isn’t afraid as well. I think both Steven and Connie, as much as they loathe Kevin, are to an extent afraid of him. He violated their space and consent. And he kept coming. As children, that was terrifying for them, because I’m almost certain they’ve never been in this kind of situation before. And Stevonnie, realising this, and also being the one at the forefront of experiencing this in Alone Together, is afraid. I’ve written multiple times that Steven and Connie are a great relationship. But they prefer to have the comfort of each other in person than they are alone together (hence the episode title), and unlike Garnet, who prefers to be one person.
To help cope with the fear, their first instinct is to unfuse. I don’t think these thoughts ran through their minds as a step by step plan, but these were probably what they were feeling, even without their knowledge.