The slight signaling occurred when Angela was unusually affectionate to Jimmy when he was about to leave for out of town business - this was a tip-off, in television narration, that something unusual would soon happen with Angela. I thought Angela would be leaving Jimmy, which she did, but not in the everyday sense of the term.
The somewhat justified part of the ending concerns Manny Horvitz. An assassin whom Manny knows was sent by Jimmy almost killed Manny last week. He thus has every reason to want to return the favor, but not with the "almost," to Jimmy. His showing up at Jimmy's house was no surprise. Neither was his finding Angela sleeping peacefully in bed.
But Louise walking out of the shower, and receiving Manny's gunshot before he realizes that his target is not Jimmy - that was jolting indeed, to us as well as Manny. So was his shooting Angela - stunning to us - and firing more bullets into both of them, to make sure they were dead.
He did this, presumably, to make sure Angela didn't go to the police about Manny shooting her lover. There was no need to kill Angela to keep this from Jimmy, whose man Mickey who went to Philadelphia will no doubt reveal what he told Manny. Or, if he doesn't, Jimmy will realize that anyway - even if weasel Mickey denies it. Or, if Manny killed Mickey, that would tell Jimmy the same.
But Munya aka Manny is one butcher not to mess with. And Jimmy brought this on himself - if you're going to aim at the prince, or even someone who has specials on assholes (Mickey's way with words), you better make sure you kill him.
So in less than a minute, Boardwalk Empire has been changed forever. Who will take care of Jimmy's son? (Speaking of whom - where was he during the shooting? I guess Angela had him staying with friends, to give her and Louise the house to themselves - but this could have been made a little more clear.) Jimmy's mother could have a bigger role - always welcome - but the Commodore may be recovering, and her attentions required there. And that's just the family side. What this will do to Jimmy professionally - what he'll do about Manny, and for that matter Lucky and Al, unhappy about the stall in the liquor flow, should make for riveting viewing. Could an re-alliance of necessity with Nucky be in the works?
And see also Boardwalk Emipre on HBO ... Boardwalk Empire 1.2: Lines and Centers Power ... Boardwalk Empire 1.10: Arnold Rothstein, Media Theorist ... Season One Finale of Boardwalk Empire
The Plot to Save Socrates
"a Da Vinci-esque thriller" - New York Daily News
"Sierra Waters is sexy as hell" - curled up with a good book