// Our pvp mode class, travels between scenes (A,B,C)
class PVPMode : MonoBehavior {

    list<Enemies> _enemies;

    void Awake() { DontDestroyOnLoad(this.gameobject); }

    void Update() {
        if(TenMinutesPassed()) {
            _enemies = GetNewEnemies();
        }
    }

    // we got to the scene A and clicked on pvp ui objects which got active
    public void OnPVPUIAwake(PvpUI ui)
    {
        ui.SetEnemies(_enemies);
    }

}

// I sit in scene A!
class PVPStartup : MonoBehavior {

    void OnEnable() {
        var ui = GetComponent<PvpUI>();
        findObjectOfType<PVPMode>().OnPVPUIAwake(ui); // could cache the value but it's not the main trouble right now
    }
}