Don't want to see pointless drama .... Aka them not knowing how to act around each other all of a sudden, leading to fighting about pointless stuff, being overly self conscious and ending up hurting one another, you know the usual.
I don't really see this happening with these two. Adachi might gain a little bit of confidence in their relationship from this, not having to worry about someone (Tarumi) snatching Shima away from her, but will likely still be her catastrophic self, while Shima has long accepted Adachi's Adachiness and is unlikely to be bothered much by anything that might happen, especially now that she's actually agreed to go out with her.