Prop runaway: options
Easy to judge from the couch and not being in danger:
vyse and zero thrust on the engine will keep the prop well below max. RPM when the propeller is at it's most fine position with no pressure against oil pressure.
Some reduced positive thrust will be possible at blue line with max. RPM.
Shutting down the engine doesn't help at all, because the propeller continues windmilling. You can't feather a runaway prop unless cutting oil pressure and having left some opposing pressure (nitrogen or spring). Windmilling engine creates its own oil pressure.
Even a very lightly loaded TwinCo will hardly hold 3000 ft with a windmilling prop.
These thoughts are no judgements for the decissions on this flight, but should help others in a similar case.
Regards and safe flying,
Andi