Nora, I watched that interchange around 9:00 this morning, too. Newman briefly left the eggs but came back in a few moments. Then a larger peregrine landed on the nest box perch, and I was puzzled that Newman did not leave the eggs. Listen to the sounds from the larger bird that came and went. Doesn't sound like Savanna at all. I think it is an interloper who has been hanging around and perching in the branchy trees near the cedars in the direction of the locks.
Well after all that speculation, I went back and did frame-by-frame on rewind. The mystery bird is indeed NOT Savanna. Leg bands are not blue, but black. I think it is the other female that was here earlier in the season.
Stay tuned, Savanna and Newman made a regular change at 10:00, See next pics. Whew.