Entering here, the timer starts and the door is electronically blocking. Jill has four minutes to exit the Treatment Room. She must obtain the Red Card Key to release the lock. The penultimate fight between Jill and Nemesis takes place here.
The remains of mysterious unidentified creatures can be seen littering the room, along with the corpses of various Umbrella researchers and facility workers. There are five switches within the room, that open the acid pour upon being turned. Shooting them, like all other destroyable objects will activate them. Early cutscene before the battle shows that Nemesis was accidentally damaged by the acid and most of his tentacles were dismembered. After this, the Nemesis will become slow and limping. The monster has enhanced amount of HP in this battle, so the acid can help Jill in defeating it. Also, if the monster sees the upcoming acid pours and it can avoid them. If he was trapped for a certain times, he will became decapitated and will start to attacking the environment while being blind. Keeping distances is the key to the victory. In this fight, the monster can use his impaling tentacle attack. Defeating Nemesis will reveal the Red Card Key.
Not defeating Nemesis and exiting the room in under 4 minutes will result in Jill being killed when the treatment process starts. If Jill is success in exiting the room, a FMV will start, tentatively named "Treated To Resurrect" after the music played during it.