The most basic parameters for a narrowing would be readily available in an acting 101 class: YOU NEVER PLAY BOREDOM. Boredom is never a motivation, unless your motivation is to bore your audience. You can play someone attempting to appear bored. This demands a second level of intention, or the primary intention. Therefore, direct "apathy" as the main intention is not the right choice. For me to play the moment with that level of flippancy would ruin the piece. It would negate the entire action of the play up to that point, even if it was the playwright's intent for the character, which I highly doubt to be the case.
The next choice on the list is "cloaked devastation". This choice, ordinarily, would be my first. First of all, it allows me to play two levels of emotion in a single moment, which is always wonderful fun! As humans, we all have the face we put on for the public eye, and behind that facade is what is really going on. We are intelligent and abstract creatures, with the ability to cloak ourselves in ways that other animals cannot. This abstraction is a fantastic tool for the actor, to create depth and subtlety, and bring true life to a person who never existed except in the mind of the writer. Audiences identify with this
much more readily than they do with a Joey Lawrence (Blossom),
for whom everything is on the surface. It's not believable that there would be a real, two dimensional human. Such a thing is very rare in our species...
However: The way this play is written is leading me to suspect that the answer is actually "a contentedness with his calculated victory". I must tell you that I am not very excited about the prospect of this being the answer. It's less meaty a choice than "cloaked devastation". It shows that Teddy somehow had prior knowledge of the end of events and organized them in some way. Omniscience is akin to boredom or apathy. It indicates a lack of journey for the character. If the playwright intends for the character to be a function in a greater metaphor, rather than a whole person
(David Mamet, "Speed The Plow")
Mamet is notorious for writing half-characters that prove nearly impossible to play with any sincerity--for this reason Mamet is proven in my mind to be a megalomaniacal sociopath, albeit a brilliant writer), such as Shakespeare does with many of his characters (CHARACTER DIMENSION article), then the actor playing such a role is hemmed in to a limited mindscape that serves the function of the play. At this moment in the process, I am leaning toward this conclusion due to the clues I have unearthed through analysis. I do expect my interpretation to morph, and I am hoping that it moves toward a more dynamic conclusion.
Wish me luck!