To me the way she holds the knife is unnatural when you look at the wound. The wound is deeper on her right side of the neck. But with how she holds the knife, the wound should have been deeper on the left side.
This does not explain the footprint though. I thought it was strange that the panel on the previous chapter does not show any footprint or blood on the knife when Hajime looked outside from the bathroom window. Was there really no footprint/blood or it was just drawn that way to show that the lightning was inadequate?
There is something strange with the garden. The small stone seems to have been moved closer to the big stone.
The footprints are unnatural as well. Why would she walk through the small stone to reach that spot?