All right, I'm really thinking I'm an idiot here. I had no idea what was going on at the end until I watched some of Talking Dead, which explained it. Here's what I thought was going on:
Siddiq was going through some screwy stuff and he was obviously a nutcase. When Dante came to check on him, I was really afraid that Siddiq was going to kill Dante because he was so unstable (Siddiq, that is). Then Dante said "Open your eyes" which were trigger words for Siddiq, and that set him off his rocker. So he started eyeing the chair to bash Dante with, but Dante saw it and intervened to stop it. Dante put the crazed Siddiq in a hold and tried to calm him down with "Close your eyes". End show.
Then Talking Dead came on and explained that really, Dante was a Whisperer spy, which is why Siddiq has had reservations about him, and he killed Siddiq! I didn't even know that Siddiq was dead lol! Am I really that stupid?
Also, it looked to me like Siddiq had switched the water to "Undrinkable", causing the epidemic. But now that I know the above, I'm thinking Dante switched the water, and Siddiq just did it trying to recreate what had happened? I guess? Is that right?
As for the rest of the episode, all I have to say is this: You don't tug on Superman's cape, you don't spit into the wind, you don't pull the mask off that old Lone Ranger, and you don't spit food in Carol's face.