Sometimes the players just forget to open the door. I was doing a one-shot with a friend, playing SW5e. He had opened a couple doors already, but this time he approaches and says:

Player: "I ring the doorbell"

GM: "You are met with silence. Nothing happens"

…

Player: "Helper droid, help me get this door open"

GM: "The droid approaches the door. He slowly turns his head and you feel his photoreceptors bore into your eyes. He extends a digit and, while maintaining eye contact, slowly presses the door open button. The door opens with a pneumatic burst. 'I am happy to problem solve for you, Master. Is there anything else you need me to do? Turn on a light, perhaps? Make stim tea? I do enjoy extending myself behind my core programming as an assassin.'"

Player: "'Shut up and guard the door.' I step inside the room, what do I see"

GM: "As you cross the threshold, two automated turrets drop from their enclosures in the ceiling. Surprise round, roll for initiative"

It was a fun game. For me