If I may be so blunt, perhaps now is the time to be working on a plan based in reality down to the detail - especially if said plan also involves being within the castle?

[Alucard understands that magic works. That blood is magic in and of itself, but the particulars have never been a strong suit. So he can be sympathetic to exactly how much trust Trevor seems to place in this plan being successful.

What that doesn't mean is that he'll allow for something half baked to go as planned without some kind of damn back up.]