By that point, the clock was becoming more of an issue than the defense. Mesko is a good punter, I watch him play every week. Even if you shank it out at the 15 or 20, and not coffin corner it out at the 2, or get a touchback and they still get it at the 20, that is 20-25 more yards they need to go with the clicking ticking away on them instead of getting it right on top of Flying Elvis.
And there was a fumble on the play, Denver could have just as easily recovered and ran it all the way back and score in 12 seconds instead of 2:30 or however quick they could go 82 yards. With timeouts intact an the 2 minute warning left as well.
They run that play all the time though, no sure points and no sure field position if you punt. Plus Gostkowski has looked like he's been drinking from the same well as Billy Cundiff lately, so you don't trust him to hit one from deep on a rainy day.