10) When he asks you, "Will it be ... YOOOOU who solves the crime?" say no. Explain to Edgar that his love of theme parties has gone too far. He throws too many of them, and everyone else is way too OK with that.
11) When Edgar asks, "What ever do you mean?" say, "Your foam party last year -- everyone got pink eye. Your summer Luau -- you didn't need to slaughter the pig in front of us before you roasted it. Children cried. Last week's Christmas party did not necessitate the hiring of little people to play elves. I walked in on an elf shitting in your toilet tank. These parties never go well. I don't see how the murder mystery thing can fare any better. Sorry."
12) When Michael wakes from the dead to say, "What a buzzkill ..." and Edgar, seething with rage, calls him an idiot for breaking character, say, "See. That's what I mean. Too serious. I'm done."
13) Top off the flutes with Champagne. Add a maraschino cherry to each glass to garnish.
14) When the lights go out, followed by a much more believable scream than the one from before, actually feel impressed by the performance going on in the living room.
15) Mix 3 ounces shame with 1 ounce regret.
16) Place the cocktails on a serving platter, and take them to your guests. As you begin to say, "Guys, look, I'm sorry," be taken aback by the sight of Edgar covered in blood with a knife stabbed into his heart. Barely notice how the atmosphere of fake fear in the room has become very real.
17) Ask, "Wait, now I've got to solve his murder too?" and then be stricken with genuine fear when Stephanie says, "He's ... he's actually dead," after she checks his pulse.
18) Shit your pants. (This step can be taken literally, if desired.)