You can create a new role with the required permissions specified in the following link:
https://help.mypurecloud.com/articles/monitor-in-progress-interactions/Also, I guess it depends on what you consider Supervisor access. You certainly don't have to give them the PureCloud Supervisor role, but you do have to open on the permissions mentioned above.
Since you may not want to manage role assignment every time you get a new trainee, you can setup a trainee group and apply the role to that group. Then you just add and remove users from the group as needed.
Thank you,
Daniel McLeod
------------------------------
Daniel McLeod
Qsect LLC
------------------------------