SPOILERS
Note what exactly a totem is, word-for-word, then look for what the level below the dream-state (when you die and go into a coma) really is.
Also
SPOILERS
I had this thought that, if he were dreaming, wouldn't he see his wife? So, basically, there are like four levels.
Level 1 is what 'may be' with his wife killing himself to reach
Level 2 is what he considers real life
Level 3 is the dream-state
Level 4 is the coma-state
Now, if Cobb was in level 1,3, or 4 he would see his wife. Only in 2 would he not. Wouldn't that make him be awake, since his wife is not there?
Anyway, just something to think about.