i whant to die in cart.php

hi, I am trying to make the script die(); in cart.php (administrator\components\com_hikashop\classes\cart.php)
but when the code die(); is executed the script redirects at another internal page without dieing.
"I know they say that I shouldn't use die(); But i do and will so dont tell me not to."
In other places of the code die() is working fine, why not in the cart.php? its like something is resuming the code and skipping die if occurred.

hmmm nope I am sure I am putting it correctly. I am using die(); at function updateEntry.
for example
function updateEntry($quantity,&$cartContent,$product_id,$add,$resetCartWhenUpdate=true,$type='product',$force=false){
echo "ok";
die();
.
.
.

but it seems that when die occurs it redirects me to option=com_hikashop&ctrl=product&task=listing&Itemid=87
hint could be that if i put some code that produces an error for example

function updateEntry($quantity,&$cartContent,$product_id,$add,$resetCartWhenUpdate=true,$type='product',$force=false){

dfsasadsadas
.
.
.

the "dfsasadsadas" will be the error, it will not redirect me but crash. So there is no Try catch at the top of the hierarchy. Weird.. any hints? its like breaking and returning when the die happens.

thanx! now i can debug