No vibrations (in the sim),
That is correct. In the full flight level D simulators I am familiar with, the actuation of the "Engine Seizure" selection starts the process with an instant very strong shaking of the simulator plus a loud noise of the engine winding down in RPM. When the seizure is complete, the vibration and noise level ceases. This is a CMF56 engine. On the same simulator a failure of the auxilliary gear box shaft exhibits the same charatacteristics as you describe.i.e N2 runs to zero and the engine flames out. This is not by defintion Severe Damage