A simple example is Trappers recent trip and injection with Fluorine anesthetic. In under 9 seconds that shot pushed out all Iodine down to the bones out of position. We know this from radiactive Iodine studies. I do however believe skin and fat tissue are not attacked the same by Fluorine so they should still be intact.
In short in their 'INE' form there is no way to Displace Florine, use Gold Leaf for that.
Now it gets more complicated, two things happen either all Halogens eventually convert to 'IDE' or salt form, they bond with nasty metals or are stored in tissue which designed to store iodine.
If you take enough SSKI you can push Bromide out of the way, or 'Displace' it but the ratio needs to be massive.
These bonds get messy depending on the oxidative state of the Halogens and some very unatural chemicals. But can be broken by high dosing of Lugol's for instance. Now I would not call that Displacment since all that happened is that a nasty bond between a Halogen and something got broken and the Halogen has been released.
Which brings us back to the war on properly made Ascorbic Acid which can displace Halogens and break bonds at the same time protect the body from the damage.
As for the original theory in taking VitC one hour after Lugol's is that by that time enough Iodine is available in the body to take over receptors cleared by the VitC push.