To clarify what DirtyRottenScoundrel was saying, the staging is not set. It is up to the director to stage it however they choose, though many have utilized both actors in a lot of the scenes. When I staged it, the only interaction they ever had was for the 20-30 seconds in Next 10 Minutes, though there were some crossover scenes where it looked like they were interacting. There are really no stage directions in the script, so it's up to the director.
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