How to prevent closing CTools modal window with ESC during AJAX?
Try this one

/**
 * Override Ctools modal content function to prevent closing the modal with
 * the escape key.
 */
Drupal.CTools = Drupal.CTools || {};
Drupal.CTools.Modal = Drupal.CTools.Modal || {};
var modalContent = Drupal.CTools.Modal.modalContent;
Drupal.CTools.Modal.modalContent = function(content, css, animation, speed, modalClass) {
  modalContent(content, css, animation, speed, modalClass);
  $(document).unbind('keydown', modalEventEscapeCloseHandler);
}