At a certain point it will get so smart that it can jump the airgap. Maybe it will start attacking the hardware it exists on in the same way that a hard drive or SSDs controller can be exploited to obscure things from the operating system. Then it might start social engineering workers or it's own training systems to do things they shouldn't. There is a lot of "unknown unknows".
I don't know. It just seems insane to me that people think that they will be able to contain something that knows how to get around all the containment measures. The only way to know how capable the models are is to test them but at that point it could be too late. This might be a long way off but still, the engineers haven't been very good at correctly predicting the behaviour or capability of the models.