Infinite Regressor Banquo

Several torturous hours went by, and the mahogany door swung open at last. An all too familiar head poked through the doorway.

Should I run up to apprehend this would-be murderer?

No, even if I stopped him now he could cook up an excuse and retreat from the chambers, there were still many days left for Macbeth to do the deed. 

I had to catch Macbeth red-handed, right before his dagger made its bloody mark. 

The hand on my sword trembling, I watched Macbeth tiptoe towards the bed, teeth chattering, with his cursed daggers clenched in each shaking fist. He did not notice me. 

Eyes screwed shut, he raised the silver blade above the king's sleeping face—-

"Macbeth!" 

I leapt out of the darkness and wrenched the dagger out of his hand before it plunged into the flesh. Both daggers clattered to the floor.

Macbeth whirled towards me, glassy eyes shaking.

"Banquo? Macbeth?" The king sat up groggily.

My fingers were numb, trembling uncontrollably as I attempted to draw my sword. 

In a lightning quick motion, Macbeth snatched the dagger up from the carpet. The blade drew a perfect arc in the air and in a blink of an eye the king's head lolled, eyes unseeing. Blood poured from his neck onto the feather-white pillows. 

"No–" I stumbled towards the body, barely noticing the dagger behind me that was now heading towards my neck.

I heard a wavering whisper, mournful but solemn, nearly lost in the shriek of the owls: 

"I'm sorry, brother."

I had died once again.