Put them on ferries on the return trip and ship them to Fujian. I am not advocating for meat shields but it sure would look bad if one of these ships were attacked....Looking at the refugees trying to get out of Ukraine via train or via car, taiwan is an island so chances are we'll be seeing more of a Kabul 2021 airport scenario than anything else. For humane reasons, China after capturing the airports of major cities should allow an air bridge for refugees fleeing taiwan, however i can see this being abused by economic migrants looking to flee to the West, not to mention allowing criminals and fugitives to escape Chinese justice.
Should be plenty of accommodation etc available down in Xiamen for these refugees to wait it out in relative comfort and the language/cultural (being Hokkien) as well as plenty of Taiwanese already there to pacify some of them.