Sago miners tried to escape
This answers the question:
The men trapped inside the Sago Mine tried to bulldoze their way out in a mine car before following their training and barricading themselves behind a makeshift protective curtain, according to the family of the disaster's sole survivor........Rick McGee, the brother-in-law of survivor Randal McCloy Jr., said Tuesday that International Coal Group Inc. chief executive Ben Hatfield told the family that the miners apparently tried to use the same mechanized mine car they rode into the mine to force their way out, but debris blocked their path.
"They found footprints," said McGee. The men "tried to go back out of the mine. This ain't hearsay. This came from Hatfield's mouth."
This answers the question of why they did not escape, but not why they did not walk out. The answers only lead to more questions. I would guess they felt their way back to the man trip and plowed into the debris, not being able to see they figured the shaft was blocked and returned to the face. That is just my opinion with what has been released.
The article goes on to suggest that wireless communication could be used. I agree. With the proper set up of antenna this could become a standard in all mines. That is the type of things the joint hearings should address.