Thank you for all the suggestions.

I just got enough time to jack the car up this morning and get under there.

The front flex disc failed completely and is broken in 3 pieces, almost exactly like that severe example you showed. So I imagine that noise was the interior of the transmission having a bad day...

My flex discs, center support + bearing are all genuine mercedes (I do my best to only order Lemforder or Genuine Mercedes). I'm going under to install them now. I have school in a few hours so I likely wont finish until tonight.

Is there anything I should do to check the health of my transmission besides take a look at it from the outside to assess damage? Or should I just replace the flex discs, center support + bearing, and take it for a slow ride to see if the noise persists?