こらー!らくがききんしー!

Erika is drawing graffiti.
Apparently, she was doodling on the tank (in Chapter 3, she drew a picture of Maho on Tank III).

Heyー! No doodlingー!

English:

Erika is drawing graffiti.
Apparently, she was doodling on the tank (in Chapter 3, she drew a picture of Maho on Tank III).

The artist is referring to Das Finale episode 3. You can see the picture that Erika drew @ 28:52.