It's hard for Hawke to wait. He's not good at that sort of thing, far more used to acting on his urges immediately (and putting off or 'forgetting' other committments he's made temporarily). But he can also be remarkably single minded, and so after he has given the two days he decided on, he shows up at the shelter again.

This time with a massive Mabari in tow.

There may have also been a call or two to the front desk ensuring Anders would be working today, by a mysterious man who never offered any contact information.