Chapter: SCENE VII.
The gates of Corioli

TITUS LARTIUS, having set a guard upon Corioli, going with drum
and trumpet
toward COMINIUS and CAIUS MARCIUS, enters with a LIEUTENANT,
other soldiers,
and a scout

  LARTIUS. So, let the ports be guarded; keep your duties
    As I have set them down. If I do send, dispatch
    Those centuries to our aid; the rest will serve
    For a short holding. If we lose the field
    We cannot keep the town.
  LIEUTENANT. Fear not our care, sir.
  LARTIUS. Hence, and shut your gates upon's.
    Our guider, come; to th' Roman camp conduct us.       Exeunt

 Outside the gates of Corioles, Titus Lartius and a bunch of Roman soldiers have stayed behind to guard the city they've just sacked. Shakespeare ups the dramatic tension by letting us know that if Caius Martius and his troops lose the battle in the field, there's no way Rome can keep the city....

