Oof... that's hard in 3, I feel ya. Well, so first, go to the door and hide behind it. Then yadda, yadda, yadda, help stuff on the key, then with correct timing, you should be able to hide behind a car for a while. And then again, run up to the key, and grab it, then run behind the car. then, run along the wall, (if timing is right you should do it), then get behind the door, and unlock it.
My first few attempts were unsuccessful. Once I was so close to unlocking the door before the oni got to me, but eventuallly I got the hang of it and made it to the door. Takes a few tries to do it.