As Chase is going after the munga himself, he assumes Eiji does, in fact, know what he's in for. And that's why he's standing back and watching for a bit.

Until the munga veers and comes right for him, that is, prompting Chase to pull out something that looks very suspiciously like a gun. (A purple gun, but a gun nonetheless.)

"Move out of the way..." It shouldn't be too difficult if Eiji's chasing along behind the munga and Chase is in front of it, but just in case.