You double down on your insult and call her delusional. You let fly so many insults about what a stupid idea it is to apply something some people theorized about a hundred years ago into something practical. You insult her raspberry pi-3D printer rig and how it would never even be able to sample finely enough to duplicate a candy bar!
Sarah is angry and goes back to working her proofs ignoring you.
What do you do?
Double Down Again, she needs to see reason!