Le An's composure and steadfastness throughout the interrogation, and the fact that he didn't expose Taras even for a moment, had, in some way, managed to block the flood of anger Taras had been feeling toward him.
Calling Treasure stupid for letting such an opportunity slip away didn't feel right, because the way he lied one after another proved that it wasn't out of stupidity or fear, it was a deliberate choice.
When Le An had saved Taras's life that night, calling him cowardly and foolish had initially been the easiest reaction for both Maxim and Taras. But after what this tight-lipped, timid Treasure had done this time -after going so far- calling him cowardly or foolish had completely fallen out of the equation for both of them.