The amount of times I have thought with my Muscovies, 'right that's it, she's off tomorrow' and then they come wandering out with a dozen or so, seemed like it was way over their full term sitting, so I wouldn't be so hasty.
And they can sit on loads of eggs, don't interfere, just leave them to get on with it, Muscovies know what they are doing. We had one a couple of years back who came out with a hatch of 17, all survived, doubling my stock at that time.
We take their eggs now for eating as they're great poached and only let them sit on a few although we do get some escapees, one of which came out 2 days ago - an all white Muscovy with blue eyes and 6 teeny bright yellow chickalumps, just lovely.
Give her a day or so yet I'd say, and leave all her eggs there, you never know...