Mirelle's mood was completely soured and bittered upon hearing Leonard's explanation. As much as she wanted to call him heartless, he was merely adapting to the rules of Velastra.
She knew deep down that he did care about the others, regardless of their status and identity.
Otherwise, he wouldn't have gone out of his way to make a payment and even throw in a warning threat.
Unfortunately, the circumstances prevented him from openly behaving in such a manner. He needed to keep up with his disguise as a calculated merchant.
In fact, what he just did could be considered a great risk already if it were to be resurfaced later on.
While Mirelle wondered how Leonard could explain his action, she was swiftly enlightened.
"The three women managed to stall the berserk slave here for you to kill, enabling us to have some clues about the incident. That alone is worth the 6 silver coins." Leonard made sure to raise his voice loud enough for the other lurkers to overhear him.