All the Guard somehow get captured, all of them, Booker and Niles included, but it’s silly to think someone like Merrick doesn’t have some shady government backing of some sort, who in turn quickly see what an asset it would be having living and unkillable weapons at your command. So after they let Merrick take all the samples he wants from the Old Guard, they swoop in and snatch the immortals up. (Think shady deep-secret Winter Soldier level stuff).

The Guard quickly prove how unstoppable they are, going on missions for their new masters and hating every moment. How are they controlled and willingly come back without being forced? Love. They won’t leave their family behind, if a team is sent out, one or two are kept back at base, locked up. Joe and Nicky are never allowed out at the same time on missions, guaranteeing they always come back. Andy is an army of one, but she won’t leave any of her family behind, their all supper protective of each other. And their handlers use this to control them, reward them and or punish them.