No, the brew wasn't poisonous in gas form yet, otherwise Marek's last act would have been to cast a charm to contain it. He was probably going to die by poison someday, but he knew from experience that Melinda would be the one to come and attempt to rescue him, it wasn't like this was the first time he'd accidentally poisoned himself.
He swallowed reflexively, and came to with a cough; the bezoar had gotten stuck in his throat, but it was already starting to help. He gripped Melinda's arm and pulled himself into a sitting position, putting a hand to his chest as he got it down, swallowing again and making a face at the feeling in his throat.
Then his eyes focused on Melinda, and he gave her a weak grin. His grip wasn't strong either, but his strength was coming back to him. "Hey," he said. "Nothing like a bezoar down the throat just before bedtime, is there?"