As far as I'm aware, PMQ is only used to "protect" data being written back to the database (or, in the case of Dialer, from the ODS to the CCS.) This is intended to mitigate against situations where the receiving server (CCS or DBMS) is not available.
Sadly, communications between subsystems on the same server are not protected in this way.
I could be wrong, but that's my understanding....