[Without a push, it's unlikely either of them would be the type to jump headfirst into something crazy like this as they are; the problem is when you combine Lenka's stubbornness with Jaune's curiosity, and they somehow manage to push both common sense and sense of danger off a cliff somewhere. That's probably what's happening here.

There's no one home just yet, this early in the evening -- the sun has only just gone down, and Lenka's parents are either still at their respective jobs or out drinking with coworkers, you know, the usual salaryman stuff. Contrary to his reluctance, once they get to his room he's actually carefully packed a few things already, including snacks and water. There's a decently heavy shovel leaning against the wall of his room that wasn't there before.

He stops to contemplate his preparations, then turns to his friend.]

Did you bring anything to protect yourself?

[They did agree to try to prepare, to some extent, but Lenka's usually one to overprepare. It's best to be safe rather than sorry, especially now that they're breaking curfew too.]