entityfieldquery for returnining distinct links to a taxonomy category for a term

gistfile1.php

<?php
        $query = new SysbioEntityFieldQuery();
    $query
      ->entityCondition('bundle', 'event')
      ->fieldCondition('field_event_type', 'tid', 'NULL', '!=')
      ->addTag('distinct')
      ;
    $result = $query->execute();
    $nids = $result['node'];
    $fields = field_info_instances('node', 'event');
    $field_id = $fields['field_event_type']['field_id'];
    field_attach_load('node', $nids, FIELD_LOAD_CURRENT, array('field_id' => $field_id));
    foreach($nids as $n) {
    $item = field_get_items('node', $n, 'field_event_type');
    $link = field_view_value('node', $n, 'field_event_type', $item[0]);
    $link['#options']['attributes']['class'][] = 'block-event-listing';
    $output[] = $link;
    }
    return $output;