Contrary to popular belief, Blaise was not an imbecile. He knew she didn't find his concern touching. Hell, she likely didn't even believe he possessed the ability to be concerned about anything beyond himself. He did, but in this instance he most likely didn't truly care.
If he was going to have to continue to listen to someone gab on and on about the various relationships they had, he rather return to the Slytherin car and listen to their drama than be forced to deal with Dani. Blaise felt she was trying to push her opinion and he wasn't in the mood to quip at anyone.
"Well, enjoy your friendships," he said flatly as he stood. "I'm sure that you all get along most excellently." With that he pulled the door open and headed out into the corridor and back toward the Slytherin compartment.