Related entries in Matrix field
As Douglas mentioned in the comments, if the relation is defined within a Matrix block, then the Matrix block is the source of the relation; not the entry.

Soy you just need to change relatedWorks and relatedPerformers to:

{% set relatedWorks = craft.entries.section('Works').relatedTo(block) %}
{% set relatedPerformers = craft.entries.section('Performers').relatedTo(block) %}