He wasn't opening the door, she was from the ither side to go into her dressing room
I didn't think she was holding the door open because she had her hands full of costume - when she appears she's got her hands full of dress and two coathangers. Plus the handle was on the outside (as in, the handle was on Tom's side of the door to push it inwards). Tbh I assumed he was holding it open with his foot!