This isn't a likely scenario at all. Eila never gets hit. That was pretty much the whole point of one story arc, no less.

Unless she let Sanya do it

That's basically exactly what it says on the artist's pixiv-page. She's playing with Sanya, and is letting her hit her.

didnt anyone noticed the bad anatomy?

nice pic :)
But what we needed is a wet t-shirt contest of (more or less) all witches.
The abbreviation "WW" can be translated with "Wet War" and not "World War" ;)
And that would be a pretty good war, that i would fight everyday ;)