Macbeth confesses to killing Duncan's guards after seeing the murdered Duncan. His explanation is as follows:

"Who can be wise, amazed, temperate and furious,

Loyal and neutral, in a moment? No man:

The expedition of my violent love

Outran the pauser reason. – Here lay Duncan,

His silver skin laced with his golden blood;

And his gashed stabs looked like a breach in nature

For ruin’s wasteful entrance: there, the murderers,

Steeped in the colours of their trade, their daggers

Unmannerly breached with gore. Who would refrain,

That had a heart to love, and in that heart

Courage, to make’s love known?"

He gives several reasons for killing the guards even though they would be the only witnesses to Duncan's death. List one.