The cruise was probably booked last year with a hefty deposit. Very difficult to cancel, especially if the CDC was telling them it was A-OK to travel if there were no symptoms apparent.
She'd have been scheduled for vacation days then, if that's the case.
That's why there's travel insurance. One call to the cruise HQ stating you were around Duncan and they'd be writing out a full refund before you hung up. Was that hefty deposit worth being stranded out in the middle of the ocean? How about that lovely scenery and beautiful sunsets inside your room? People don't think anymore. These nurses should have the common sense not to travel. Period.