Excuse
Because Captain Toshiro Hitsugaya is just so busy. He doesn't remember the last time he felt the pressure of incoming deadlines and incoming messages and important meetings and oh, he's just so busy! But he knows this was just an excuse to avoid her. Today is no different, and everyone in the 10th division barracks knows that he wishes to be undisturbed.
In his defense, it wasn't necessarily untrue, since he does have all these documents that Rangiku had failed to sign and he simply doesn't have the time to socialize because of said documents that he has to sign.
It's also times like these where he is grateful for Rangiku being the way she is.
And it's not like he doesn't want to see her- no, not that at all. Karin is his best friend. The only one he trusts besides Matsumoto. The only one who understands him in a way that Momo never understood him. And he appreciates her for that. He's glad he met her.
It's just, he wouldn't know what to say to her.
But he mostly worries about what she would say or what she would think of him.
Stay busy. He tells himself.
He'd much rather distract himself with work than to confront the issue at hand.