Trent:  Explain the gold medallions to me .
Breech: The time mirror works safely only one way ; coming into the past from the future .
Trent: And when the medallions are pulled off ?
Breech: They 're focusing elements for the mirror . It 's ... it's - it 's as if time were a rubber band , and you were on one end stretched out tight . As long as the medallion 's present , the band stays tight . But when you rip it off , we snap back up to the future .
Trent: I 'm wearing _ one _ . That makes me vulnerable ?
Breech: Yes , you 're vulnerable . And we 'll get you . We 'll have to get you , finally . If you kill me , another will take my place . And if you kill him , another .