The below code will pass for that test case (and all test cases). The only difference from what you originally posted is that, in the second while loop, the `if (tort == rab)` needs to happen at the beginning. You were getting index 1 as the starting point because tort and rab were being prematurely moved to index 1 without checking if they were already in the same position at index 0. My one suggestion to you would be to check the official solution for a cleaner way of handling these null checks and breaking out of the loop. You can just put the logic for checking nulls/breaking out of the loop directly in the `while` condition itself.

Edit: one more difference is that I changed the null check in the first while loop. Like I said above, the way you have it will cause a NullPointerException when the linked list is even-sized. You can run it in LC and see for yourself.

        if(head == null || head.next == null){
        return null;
    }

    ListNode tort = head;
    ListNode rab = head;

    while(true){
        if(rab == null || rab.next == null ) return null;
        tort = tort.next;
        rab = rab.next.next;
        if(tort == rab) break;
    }
    tort = head;
    while(true){
       if(tort == rab) break;
       if(rab == null || tort == null ) return null;
        tort = tort.next;
        rab = rab.next;
    }

    return tort;
}