Cade has been in an especially foul mood since the incident with Alistair. He had gone back to work, ruminating on all the things he could have said, regretting that Zevran showed up in time to intervene, at the same time knowing how much trouble he could've gotten into if left to his own temper.
It doesn't even matter to him that Zevran dismissed him and stayed behind to chew out Alistair; Alistair still won. He wins no matter what. Always.

Cade gives his customary knock on the tower door, then lets himself in, making his way over to sullenly slump into his usual chair. He should be packing for the Western Approach, and instead he's here, and it's all Alistair's fault, just like it always was.