If one falls off the way it was planned it will be a very bad but not necessarily terrible situation. Someone else already linked to the excellent admiral cloudberg article that describes how it should have happened (which there it didn't), as designed the engine would flip over the wing and not hit anything. Though of course the damage to the wing and pylon might rip hydraulics or wiring out or something. It's never a good thing.

Also, the engines are pretty close to the centre of mass so it's not a huge deal. Asymmetric thrust will be a problem but the drag situation will be better than with 1 engine disabled! After all there is no inactive engine face catching a whole load of air. And an engine failure situation is already a known situation.