[Andrew Hackard]

I'm not going to answer every question in your post because I think many of them can be cleared up with a single explanation.

If you can't beat a monster on your own, you may have one (and only one) player join you in the fight, adding their combat strength to yours for the duration of the fight. If the two of you then kill all the monsters, you split the Treasure according to whatever deal you struck when you accepted that person's help. Conversely, if the two of you cannot beat the monsters, you must both Run Away -- so you share the possible rewards but also the possible risk.

Playing cards into a fight does not constitute "help" as defined by the Munchkin rules. If I play a one-shot to increase your combat strength, I am not a "helper" as the term is used in the Munchkin rules if I haven't also joined the fight with my full combat strength.

If you have questions that this explanation doesn't clear up, please feel free to reply below. (Everyone else, please let Fufu weigh in before jumping in on this one. Thanks.)