This knowledge gave Richard positive assurance that the volleys they had heard must have been fired by some party that had fallen upon Blake's men and taken them by surprise.
And it was his fault! He was the traitor to whom perhaps a score of men owed their deaths at that moment! He had failed to keep watch as he had undertaken.

His fault it was--No! not his, but this villain's who sat there smugly taking his ease and pulling at his pipe.
At a blow Richard dashed the thing from his companion's mouth and fingers.
Trenchard looked up startled.
"What the devil... ?" he began.
"It is your fault, your fault!" cried Richard, his eyes blazing, his lips livid.

"It was you who lured me hither." Trenchard stared at him in bland surprise.

"Now, what a plague is't you're saying ?" he asked, and brought Richard to his senses by awaking in him the instinct of self-preservation.
How could he explain his meaning without betraying himself ?--and surely that were a folly, now that the others were no doubt disposed of.

Let him, rather, bethink him of his own safety.