The Quarantine Access A is a room in the Phazon Mines. It connects the Central Dynamo to the Metroid Quarantine A by a White Door and a Purple Door, respectively.
The center of the hallway is secured by four Mega Turrets hanging from the ceiling. Utilizing a small hole on the southeast part of the room, Samus can use the Morph Ball to enter a small area underneath where the turrets cannot hit her. When she comes up at the other end, she can scan a terminal to deactivate the turrets.
Two cryotanks in the room contain the unknown remains of dead bioforms.