The "deep story" is built around two biological agents named after Greek myths:
The only known antidote, which must be administered before the 20-hour window closes.
Ethan must fight his way through Ambrose’s stronghold to retrieve the Bellerophon antidote before Nyah dies. Chimera - Mission Impossible | Fandom
During a raid to destroy the virus, Nyah injects herself with the last remaining sample of Chimera to prevent Ambrose from obtaining it.