You will notice at the start of building the WHERE clause that if the search string is numeric it only searches on ticketID.
In my tickets.inc.php file at line 100 it now looks like this. It works.
if(is_numeric($searchTerm)){
$qwhere.=" AND ticket.ticketID LIKE '$queryterm%'".
" OR ticket.phone LIKE '%$queryterm%'";
Hope this helps! :