I think my favorite scene in Boardwalk Empire 4.8 is when tears well up in Chalky's eyes as Maitland sings to him. Those tears would be the turning point in their relationship so far, a turning point that would save Chalky's life.
It was those tears that no doubt got Maitland to realize that she cared too much about Chalky to let him be killed by Narcisse's man Purnsley. First she tries to get Chalky to leave. Then, in the pivotal instant, she stabs Purnsley in the back, which saves Chalky's life.
That stab in the back was a work of art. Purnsley has in effect stabbed Chalky in the back with his treachery, and Maitland was on the path of doing the same to her lover. So it's completely appropriate that Maitland turns on Paisley with a knife in his back.
It's also satisfying to see a human reaction to tears - Maitland's reaction to Chalky's - having such profound consequences. What's not clear is what Chalky's reaction will be, after he gets over the trauma of what just happened and almost happened to him. He knows that Maitland set him up - that's why we see him ask Purnsley how he knew that Chalky was at Maitland's place - and how he will mix that in with Maitland deciding at the last minute to go with Chalky will be interesting to see.
The other treachery afoot in this powerful episode is, once again, Eli's to Nucky. This time, Eli's actions are at least motivated not by greed and pride but by wanting to protect his family - specifically, Willie. Still, it's hard to imagine just how far Eli will go with this. He's not about to commit suicide, as Eddie did, so what will he do as the Feds pull the noose tighter around him?
The human drama simmers in Boardwalk Empire.