Seven surviving Martian marines regroup, penetrate the station's record chamber, and arrest Holden seconds before Miller can complete the lockdown release.
After losing their grenadier to the station automatons, the seven surviving Martian reconnaissance marines withdraw and regroup rather than abandon the pursuit. Their powered armor still gives them overwhelming physical superiority even though the station neutralizes ballistic weapons.
They follow James Holden and Miller into the central record chamber just after Holden witnesses the builders' extinction. Acting under the authority of the Martian Congressional Republic, they order Holden to kneel with his hands on his head and threaten lethal force for resistance. Holden complies. The arrest interrupts Miller at the moment he claims he can take the station out of lockdown, making Mars's attempt to secure one human suspect an immediate obstacle to helping every ship caught in the catastrophe.
Mars is represented by seven surviving reconnaissance marines in powered armor, physically dominant even without usable guns and speaking through electronically amplified suit systems.
Mars now holds Holden inside the station, but its lawful arrest arrives precisely when his cooperation with Miller may be the only route to reversing the alien lockdown.