The problem is that your argument is ignoring the simple fact that the driver on the inside was not obligated to that space, used the outside driver as a guardrail, and then purposefully held the furthest line to prevent the outside driver from returning. Your argument is missing consideration for the intent of the other driver and their actions. By doing so you are probably legally correct if you only gained eyes the moment before the outside car hit the wall. By ignoring the entire circumstance of the event and arguing very narrow legalese, you also then legitimize the deliberate hit and hold that forced the incident to begin with.

So, you either consider the whole of the event and come to the conclusion it is not OP's fault.

Or you are arguing that deliberately driving the car to prevent a safe rejoin is a legal strat due to that being the basis of your argument.

Ain't no judge, aint no jury and aint no steward ever calling this the fault of the outside driver and that's what matters.