Oscar and Elanor are in the back of the car, heading to the mental institution owned by Dr. Siltanen.
Oscar decided to visit his brother, and Elanor said that she will join him.
Elanor admires Oscar and she saw him doing many ruthless things in more than three decades they are together, but she also knows that Oscar has a soft spot toward his brother and that Marcus has the capability of taking advantage of that. Elanor will not allow Oscar to face his brother by himself, and even though Oscar asked her not to join him during the visit, just being close by will be enough for Oscar to stay firm (that's what Elanor hopes).
They are aware that Jeff put Marcus and Lukas in the mental institution as part of retaliation because Marcus tried to usurp Jeff's newly acquired position as a master.