Route 40 (Apache/Main) runs until about 10pm Saturday, longer if I'm willing to trudge to Sycamore. Therefore, I have met the condition that I can leave Phoenix Comicon whenever I want, though I'll need to recognize when social fatigue has set in so that I don't stay when I shouldn't, for such mismotivations as getting my $25 worth or, gods forbid, I meet someone whom I want to follow around. But if I arrive around noon, there should be enough panels to keep me occupied until a long dinner break, and I can conclude the evening with Wil Wheaton's talk, and leave at 7:30.
The "why bother" instinct continues to fire up, and I have no way of truly knowing whether that's the depression talking, or whether I'm truly overestimating my potential satisfaction from the event, or whether I'm overestimating my chances that drama could occur.