If it is locked at first you eventually return and it will be unlocked.
Opening locked doors in dead space.
As previously noted this skill takes a lot of practice to master so have plenty of cheap practice locks on hand if you hope to get good at it.
Dead space 2 wiki guide.
Each time you visit that level you will need to expend a power node to open that.
With your weapon in hand use a melee attack on the generator to the right of the locked door to open the way.
The doors will be unlocked.
Inside is a small button that needs to be pushed to unlock the door.
The non locking side of the door should have a small hole likely on the face of the knob.
You return to this area later in the game.
Use the leg of the pick to find and push each pin up and out of the tumbler.
Same goes for any other door in the game.
Node locked doors are doors that require a power node to open.
Once all pins have been moved the lock should open.
Insert the pick above the wrench.