They may point to the same elements but they're different containers. The Queue is not backed by that list. References to the elements are copied from the list to the queue, but if you remove something from the queue it shouldn't (and doesn't) reflect on the list.
In particular the constructor for LinkedList looks like this
public LinkedList(Collection<? extends E> c) { this(); addAll(c);}The addAll method, in turn, look like this (after calling a version of itself and providing the size):
public boolean addAll(int index, Collection<? extends E> c) { // omitted for brevity Object[] a = c.toArray(); // omitted for brevity for (Object o : a) { @SuppressWarnings("unchecked") E e = (E) o; Node<E> newNode = new Node<>(pred, e, null); if (pred == null) first = newNode; else pred.next = newNode; pred = newNode; } // omitted for brevity}(where first is the first node of the linked list)
So, as you can see, it creates its own nodes. So yeah, if you remove any of those nodes you're not removing anything from the original list.