Ladies! Please!
In the rush to find a “wrong” answer, is it possible that both diagnoses have some merit and there is not 100% certainty because of lack of detail? Faced with a completely seized engine on both rotors, it’s not going to run again until it’s left the repair shop, so there is no harm whatsoever in doing the Severe checklist. Being pedantic you could argue that it was just a rundown(!) without vibration so it just needs securing.
Both are points of view and both could be “right” but, in real life, what would you do if an engine failed (and you know this because of the yaw and loss of performance) and even though there is no vibration N1 & N2 have gone to zero over a short time interval? Would you really go “oh yes, definitely fine, let’s start it back up later”? I think I’d be checking under the wing to see how much of it was left...