So at some point, Ran has dealt with zombies in the past. This will be explained more after chapter five.

This is the first reference to "The Blight". In Maho Noir, there is a physical manifestation of evil and corruption. Tendrils of this manifestation take hold in an area and expand outwards... the area that has been taken over is known as "The Blight".

The bottom panel was referencing the scene in Terminator 2 where the T1000 has a bullet go through its head and the camera framing of the shot.