MRT Challenge

Panel 1- John: " Imagine, Marcia, we're now in first college standing in line at the MRT station.."
          Marcia: " You're right, John..Hihihi.."
Panel 2- John: " Marcia, when are you going to say yes and be my girlfriend?"
          Marcia: " When we reach the escalator.."
Panel 3- John: " I might already have taken the board exam when that happens.."