As soon as he laid eyes on her, Castiel had been ready to leave just as soon as he'd arrived. It hadn't been his intention to seek her out. In fact, it had been quite the opposite and had she not seen him, there would have been only his indecision to regret.
He hadn't desired or needed alcohol since his return to Heaven. Or at least, he hadn't had the time to do so and his Grace had for the most part, shielded him from his own vices. But now, he was alone, his world was likely gone, and what Sam had told him only gave way to doubt.
He'd wanted the drink, but now found Meg instead. When she glared at him, he simply glared back.