"I think we've already changed Thedas a fair amount," is not unkindly said. Cosima doesn't want to depress Ness, or even really to chastise her. (It's not as if Ness isn't aware that Cosima wasn't thrilled with the make it look like an accident component of the plan. There's no need to belabor that now.)

"What has Doctor Strange been saying about your recovery? Any prognosis so far, or is he still keeping that close to the vest?" It's not, under the circumstances, a change of subject so much as a reminder that all of the many experiments Ness is picturing will remain theoretical for at least a while to come.