THIS IS WHAT REALLY KILLED STEVE IRWIN

"Developed by the USMC, Metal Gear RAY differs from previous Metal Gears in that it is not a nuclear launch platform, but instead a weapon of conventional warfare, originally designed to hunt down and destroy the many derivatives of Metal Gear REX that became common after the leak of the REX plans after the events of Shadow Moses. It is designed to be even more maneuverable and flexible in deployment than the REX, and can operate both on land and in the water. (Underwater, it is propelled by engines of unknown form in its two bulbous "wings".) While RAY has a pair of machine guns and six missile tubes to defend itself from more conventional battlefield threats, its primary weapon is a powerful water jet, which can cut through heavily-armored foes, such as Metal Gear REX clones.

RAY's interior workings are also much more organic. It has artificial fibers that contract when electricity is applied, much like natural muscle, instead of typical hydraulics; this pseudo-muscle tissue makes it very maneuverable. It also has a nervous-system-like system of conductive nanotubes, which connect the widely dispersed sensor systems and relay commands from the cockpit to the various parts of RAY's body, automatically bypassing damaged systems and rerouting to auxiliary systems when needed. Another feature is its blood-like armor-repair nanopaste, which is secreted from valves whenever the exterior surface is damaged. Particularly unusual is its "face", with two "eyes" and a gaping "mouth", only seen when the head armor is removed.

This version is labeled "MARINES", and has a cockpit (accommodating a single pilot) and a long tail. The RAY is an amphibious craft which allows for maneuverability in land and at sea-- the long tail is intended for balance while making leaps or operating underwater. The entirety of the forward interior of the cockpit is a heads-up display (HUD), allowing the pilot to look around as if there were no obstruction between him and the battlefield. Unlike REX, which had its exterior sensor concentrated in a single, vulnerable radome, the sensors (including cameras, radar emitters, and an array of passive detection sensors) are distributed throughout the body."

Taken and edited from: Answers.com

REASONS WHICH LED TO STEVE IRWIN'S DEMISE:
1. Improper gear loadout.
- During his confrontation with RAY, Irwin is thought to be missing two very important items necessary should one is required to take out a Metal Gear:

a) Stinger Missile Launcher

True that one cannot expect to destroy a purely destructive armored behemoth without first packing enough firepower to destroy a whole MBT column. In this case, the Stinger missile launcher is considered as one of the best weapons when going mano-e-mano against Metal Gears. Even though Stingers were primarily developed to counter and destroy aerial threats, the warhead's armor-piercing capability gave it enough strength to punch through even the thickest armor of just about any heavily-armored vehicle in existence no matter the size or shape.

b) Ration

A soldier, no matter how elite or badass he is, will be rendered pratically weak and useless once hunger sets in. Therefore, it is important for one to ensure his daily nutritional needs are fulfilled and balanced to keep him going even when confronted against the most advanced bipedal tactical nuclear weapon. In this case, one must always keep a Ration handy at all times. One very helpful tip when trying to survive a fight against Metal Gear is to equip the Ration as one of your equipment, much as equipping a weapon in hand. Should your health reaches zero with the Ration equipped, you will be instantly revived in full health, thus enabling you to survive and outlast whatever Metal Gear you're fighting against. Unfortunately, this was not the case in Steve Irwin's epic battle against the armored titan itself.

2. Inadequate support crew.
Irwin's support vessel, Croc One, was not equipped nor was intended for anti-Metal Gear warfare and countermeasure against Metal Gear. Also, the vessel itself lacks proper military-grade tactical communications equipment. None of its crews above the vessel had any military experience or knowledge of Metal Gears and therefore were unable to provide Irwin with necessary information or survival methods during his heroic struggle against RAY when Irwin radioed in for help. The crew were also thought to be unable to provide Irwin with the correct radio transmission which enables him to save his progress before the fight began.

3. Failing to master this one very important technique.
See picture.

Based on this thread in 4Chan:


RANDOM IMAGE OF THE DAY:
Gentlemen... behold! CORN!