Let's say I'm writing a scene where Arnold and Jo are arguing over whether to go out tonight or not.
While they do this, though, Rupert is also in the process of constructing a house of cards, and Gertrude is quite noisily searching in the cupboard for some lasagne sheets.
Each of these things play out in their own time, only to simultaneously reach their conclusion:
Arnold finally gives in and cries, "Fine. Have your way. We'll go the post office!"
Rupert finishes his house of cards, only to step backwards from it and have it collapse.
Gertrude finds the lasagne sheets, and cries "lasagne!" in triumph.
(Assume, for the sake of argument, these will all be captured in a single continious wide shot.)
Are there any existing conventions about how simultaneous threads like these should be dealt with in a script? If not, what can be done to minimise the confusion for the reader.