Grissom delivers the ransom money to the kidnapper, but the kidnapper blows himself up, leaving no clues as to where Nick is buried. As the clock slowly ticks away, the CSIs must rush to find Nick who is buried underground and slowly sufficating.
When Nick is still trapped in the glass coffin when he is talking to Grissom, [When the CSI team finds him].. We see that the tissue or piece of glove he put in his ear is very long. They then show Grissom and then back to Nick and we see that the tissue is actually really small now.