Hermione thought about that for a moment. They'd talked about whether or not asking Bill would have been a good idea, but they hadn't been able to agree. She didn't think they'd ever gotten past the idea that they'd have to divulge the horcruxes if they were going to ask for help from the Order. If Bill was offering without their having to...
She looked at him, then back at the map. "There's a vault, a very old, very deep vault, that we need in to. It's likely one of the oldest in the bank." And likely to have the highest security measures available, but she didn't think she had to tell Bill that.