Mario Yuno had already pinpointed the criminal, and rounding them up was just a matter of moments; Kiara had confidence in his abilities, convinced that he would certainly be able to rescue Renee Wong—of course, during the rescue, it wouldn't be surprising if the criminal, in a fit of rage, caused Wong to lose an arm or leg or suffer some minor injuries.
Kiara didn't think she owed Renee anything, nor was she willing to take risks for this woman whose heart she'd always found lacking. She decisively refused.
Mario Yuno didn't make things difficult for her. Upon hearing her refusal, he simply said he understood, then told Kiara to stay safe before hanging up.
What Kiara didn't know was the heavy pressure that Mario Yuno was carrying at the moment to respect her decision.