I love how Fukatsu and Tomose are becoming closer. They were made to be together.
That's when they first met if all the pieces fit. Tomose mentioned doing CPR on someone before, which must have been Fukatsu since he had that vision/dream. Tomose kissed him to give him air and then pushed on his chest which is chest compression.
Fukatsu must've have barely seen the scar if he was in a half awake state during the actual event. This may explain why Fukatsu can see her face. She saved him. He remembers his savior.
I think in the next chapters, Fukatsu will ask her about the scar and Tomose will be surprised as to why he knows it and they will come to a realization that they met before, which will further strengthen their bond.