Question:
I'm at the point where I'm playing as Chris in Antartica and need to put out the fire in the lab. I found the system for refilling the extinguisher, but the fire extinguisher isn't in my item box - it must be in the metal detector back at the Prison 1F. Think I painted myself into a corner. D'ohh! Does anyone know a way to recover that item, or find another one? Do I really need it? Or am I totally screwed and have to start the game over at the beginning?

Answer: It's only use is to get the magnum and three boxes of handgun bullets. If you find the magnum extremely imporant, restart, but you don't need it to complete the game.