Much like the Open Window animation, this one took a lot of tweaking to get correct as I needed the character to move forward while opening the door so that the mesh didn't stretch and to keep the hand on handle while moving the torso. In order to get the correct positions and flow to the animation, I kept opening doors constantly to see how the body is positioned and how you move into the room after opening a door, especially in a stealthy fashion.
Starting with the idle pose again, I changed the angle on the body to get his side against the door in a guard/cautious stance. I also aimed his head towards the door so it was obvious that he intended to use the door. It also meant he could look through the window for threats before opening the door.
From this I needed the thief to grab the door handle and begin to pull it down to open the door. I simply dragged the hand to the handle and positioned it. The arm automatically found a good joint angle thanks to it being an IK.
For the gripping of the handle. I keyed the finger controller curl attribute on all the fingers to 4 and the thumb to 3. This gave a nice scrunch to the fingers and nicely fit around the handle. After this I wanted him to actually pull down the handle. Since this was a handle and not a knob, it needed a movement on the y-axis to convey the pull down as well as the rotation of the hand to maintain the grip of the handle. To do this I rotated the hand on the Y-axis around 30 degrees as I found this was a good rotation of the handle before a door opens.
Then I began to open the door to let the character in. To do this he needed to move with the door while holding the handle and walking slowly into the room. I initially attempted to have him just open the door by extending his arm but quickly realised that this stretched the mesh and looked unrealistic. In order to first open the door I began using the full length of his arm before I began to stretch. I keyed his spine root controller moving forward to give the image of him pushing the door without moving. Afterwards I began to move the character by lifting the characters left leg first and moving it to an intermediate stage and adding a slight toe roll to the foot so it pointed towards the floor as would happen when you walk. I then repeated the process with the opposite foot so that, when played, the thief would move forward into the room.
The last thing I wanted was the have the thief let go of the door handle (and the door to slow to a stop since it was no longer being pushed) and scout the room by looking around briefly. I took the starting key for the hand that was on the door handle and pasted it at the point that I wanted the hand to release the handle. Then, since I keyed the head to be looking at the right side of the room as he entered, I needed to change the direction the head was looking. This was a simple rotation of the head and keyed in to look both left and then straight ahead towards the safe.
The animation is intended to be blended together in the Trax Editor with the walk animation and key hole peek animation created by Elliott. This makes it seem as if the thief is inexperienced but cautious. Later it would blend into a walk towards the safe located in the room he is opening the door to.