Ada Wong

Although heavily injured during the events of Resident Evil 2, Ada survived her encounter with the T-103 Tyrant and retrieved a tissue sample from the dead body of the mutated William Birkin.

After tossing Leon Kennedy a rocket launcher, Ada returns to the surface, at which point Wesker then contacts her via phone and informs her that she has failed, and that her rescuing Leon would have consequences for their organization.

Ada shows Wesker the tissue sample, at which point he informs her that Raccoon City is about to be nuked. He eventually helps her escape to safety.