In the last sentence I typed "quand ils partent de mon salon !" but "partent de" marked as an error and advised "quittent" or "sortent de".
Could you please explain why "partent de" cannot be used here as an option ?
For "partir", in the relevant lesson, it is written as: "When used with a place, it will always be followed by a preposition (e.g. I leave from / for = Je pars de / pour)" Example: Je pars de cette ville.