My buddy just had his tilt Olds key that he couldn't get out of the lock when shutting off. He took it to a dealership and they put in a new ingnition switch in the column. Does the same thing after the bill and he gets it back. In that column there is a collar that turns with the floor shift so you can't turn the key unless it is in park or neutral. The timing of that collar was off.

Before correcting the problem, I could get the key out by moving the tilt up and down at the same time as turning the key to the off position.