Once the group all settled back down after Harold's assault on Lance, they returned their attention to the point that Lance had raised.
While some of them believed that it could be the physician's son. Some of them thought that they couldn't just conclude that the physician's son or someone close to the family who had access to the physician's beta's nightmare was seeking vengeance.
Even if their best bet was that the potion had been fed to Alicia and Lance, there was still a possibility that it might be some other kind of potion they didn't know about.
But regardless of whatever potion it was, the question now on all their minds was WHO? Who was this person messing with all of them?