Experience working on the side as Schuman trainee?

Hi there, I have accepted an offer as a Schuman trainee (DG Comm) and was wondering if anyone has experience working on the side during the traineeship?

The rules (Article 15) are a bit confusing and state that "They must not have any professional connections with third parties that may be incompatible with their traineeship." and "Trainees are not permitted to exercise any gainful employment during the traineeship period that may adversely affect the work assigned to them." In my opinion this is all very broad and I was wondering how this is usually interpreted.

Perhaps someone could share their experience, thank you!