She twisted her hands behind her; but all the knots held good. She writhed her hands till her fingers were wet with sweat or blood. They stretched and strained in the darkness, and the hours crawled by like years, Till, now, on the stroke of midnight, Cold, on the stroke of midnight, The tip of one finger touched it! The trigger at least was hers!
We think this scene feels like it's straight out of an action movie. The bad guys have the heroine tied up, and she struggles to get free. At first it seems impossible, but eventually she manages it and slips out of the ropes.
That's what happens here, except Bess isn't trying to escape. She's reaching for the trigger of the gun. She strains and struggles and the speaker really makes it seem like it's taking forever. Finally, at midnight, she grabs the trigger.