3 hopeless idiots

3 hopeless idiots taken in by a professor to rehabilitate their profound stupidity.

In order for the professor to address their stupidity he wanted to ascertain their level of common sense. So he went about this by drawing a door on the board and asked them respectively (from 'smartest' to dumbest) to open the door that was drawn on the board.

Professor: " student1 come try and open this door"

*student1 taps the board to find any hinges but was not able to find any"

Student1:"i cant find a hinge or knob to pull"

Professor: "alright student2 you give it a go"

*student2 bangs the board hoping the drawn door would fall or at least shake a bit" *

Student2: "the door is stuck professor"

Professor: "Have a seat then, better luck next time"

At this point there's only one dummy left however the professor could not help to notice that throughout the session the third student had been laughing and giggling the whole time.
The professor curiously asks

Professor: "You! Why are you laughing?"

Student3: "Because those idiots don't know how to open the door"

Professor: "And i suppose you know how?"

Student3: " of course, just give me a second to pull the key out of my pocket"


Professor: *FACEPALM*