Activate simple the Shuffle Mode of the slider via the option shuffle:"on". It reorders at load the slider, but till new load, it will stay in this order.
	  	<script type="text/javascript">
				var revapi;
				jQuery(document).ready(function() {
					   revapi = jQuery('.tp-banner').revolution(
						{
							delay:9000,
							startwidth:1170,
							startheight:500,
							hideThumbs:10,
							shuffle:"on"
						});
				});
			</script>