add_filter('frm_setup_new_fields_vars', 'customize_dfe', 25, 2);
function customize_dfe( $values, $field ) {
if ( $field->id == 182 && !empty( $values['options'] ) ){//Replace 125 with the ID of your dynamic field
  $temp_values = $values;
  $temp_values['form_select'] = 170; //change 30 to the id of the second field you want to show in your dynamic field
  $field2_opts = FrmProDynamicFieldsController::get_independent_options( $temp_values, $field );
  foreach ( $values['options'] as $id => $v ) {
    $values['options'][ $id ] .= ' '. $field2_opts[ $id ];
  }
}
return $values;
}