Fort: 1d20 + 4 ⇒ (12) + 4 = 16
Edit: for consistency, going forward, I'll always roll for Dromer first and Crusty second, when both are subject to a save at the same time.
Edit#2: same for skill checks, like Perception and Knowledge (after Crusty gets the ability to speak with master, aka when Dromer starts "hearing voices" in his head).