No, sorry, there is currently no official way to import/export data between CityEngine and Indoors. That is an interesting use case though, so thanks for sharing.
Indoors stores information as feature service layers. CityEngine has the ability to import feature service layers. Technically, it would be possible to import some data into CityEngine. However, it is highly unlikely that a model could be created in CityEngine using the data from the Indoors feature service layer because each product has different requirements.