Carissa wakes up the next morning in her own Palace bed, having gotten - she's not sure how much sleep, but enough. You can feel it, as a wizard, whether your mind is still sticky with yesterday's magic. Eight hours is the rule of thumb, but people do vary; some need a little less, some a little more. Carissa is about average.
Until her Ring of Sustenance kicks in, in five more days. She's carefully not thinking about how many things can happen in five days.
She's in her own bed, not Keltham's, because she didn't want to wake him up slipping into bed, or explain to him why she was out so late. She didn't help clean up the confetti, that's beneath her dignity, but she did help Maillol get through the entire backlog of project-related paperwork. If she was stupid enough to march up to Aspexia Rugatonn and ask for a desk job, she had better sit at a desk and do it. It took well into the night, but they were all squared away, by the time she went off to bed, for the relocation in the morning. Shortly after dawn, as soon as the Forbiddance was up.
The light filtering through into the adorable little courtyard suggests it's well past dawn, so probably that has already happened. Unless the fortress turned out to contain a secret tunnel to the Underdark, or Aspexia Rugatonn was assassinated in the dead of night, or they've gotten an order directly from Asmodeus to relocate the project directly to Dis instead. You never know, on Project Lawful.