While unlocking a door, press Up on a key, then immediately pause the game afterwards. Look at the tab you raised up. If it is mostly up and about to reach the top, resume the game and do it again. If it is mostly half-way or mostly down, resume the game and immediately press [Space]. You should have that tab done. Continue on with the next tab. This might require a few attempts, but after you have done it once it should be easy.