Sector 4 (AQA)
After Samus unlocked the Security Level 1 doors, the X invaded the sector and infected many creatures inhabiting it including Serris. Damage widespread damage occurred, severing wiring which electrified much of the water. This prevents Samus from exploring much of the sector. Once Serris is defeated and the Speed Booster acquired, Samus can lower the water level using the Pump Control Unit.