How ot turn off Mini-Cart when in the Cart

You need to edit the cart file of the view product in the HikaShop menu Display->Views. Near line 30 of the file, you can just change the code:
if(!empty($Itemid)){
$url_itemid='&Itemid='.$Itemid;
}
by the code
$url_itemid='&Itemid=99';

Then, in the cart module joomla options, you can restrict the display of the module to some page. You should set it to be displayed only on the pages you want it instead of "all the pages".

Also, do not forget to clean your browser's cache after the modification.