Acquire the Varia Suit

To survive the intense heat and corrosive Phazon radiation in the lower levels, you must first acquire the Varia Suit. From the Main Labs, locate the elevator leading down to the Geothermal Core. The path will be blocked by a series of heat vents. You'll need to find a way to temporarily disable them. Scan the environment for a control panel that regulates the vent flow. Once the path is clear, proceed to the Varia Suit chamber. The suit is typically found in a large, ornate chamber, often guarded by a mini-boss. In this case, you'll face a Phazon Crawler. This creature is heavily armored; target its exposed underbelly when it rears up. Once defeated, the Varia Suit will be accessible, granting you resistance to extreme temperatures and minor Phazon exposure.