Laravel Spark, Swap/Interact, and Private Variables

First post here, so apologies if I somehow violate community norms.

I'm using Laravel Spark. I want to swap in a new implementation for the configureTeamForNewUser method. At first, it looks like this is possible because of the Spark::interact call here

#File: spark/src/Interactions/Auth/Register.php
Spark::interact(self::class.'@configureTeamForNewUser', [$request, $user]);

i.e. the framework calls configureTeamForNewUser using Spark::interact, which means I can Spark::swap it.

However, if I look at the configureTeamForNewUser method itself

#File: spark/src/Interactions/Auth/Register.php
public function configureTeamForNewUser(RegisterRequest $request, $user)
{
    if ($invitation = $request->invitation()) {
        Spark::interact(AddTeamMember::class, [$invitation->team, $user]);

        self::$team = $invitation->team;

        $invitation->delete();
    } elseif (Spark::onlyTeamPlans()) {
        self::$team = Spark::interact(CreateTeam::class, [
            $user, ['name' => $request->team, 'slug' => $request->team_slug]
        ]);
    }

    $user->currentTeam();
}

This method assigns a value to the private $team class property. It's my understanding that if I use Spark::swap my callback is called instead of the original method. Initial tests confirm this. However, since my callback can't set $team, this means my callback would change the behavior of the system in a way that's going to break other spark functionality.

Is the above a correct understanding of the system? Or am I missing something, and it would be possible to swap in another function call (somehow calling the original configureTeamForNewUser)?

I'm using configureTeamForNewUser as a specific example of the more general problem. While help on the specific problem is appreciated, help with the more general problem is what I'm really after.