Provide your own definition:
A) Working under the QMS
I.E. Everyone following the procedures laid down within the QMS
or
B) Working in QMS
I.E. Those directly involved in Quality Management such as those who manage the QMS, or have a predominantly Quality orientated task (such as inspectors and auditors).
If your interpretation is incorrect, you'll at least have had a good stab at it, and any certifying auditor will be happy to provide a little guidance if they can see that a reasonable effort has been made to interpret the standard.