Carl
Cheesehead
This was one of those improvised ab lib plays that nobody expects Palmer to make. It was a broken play all the way around for both sides. That wasn't some kind of planned play on AZ's part. Nobody in their right mind expected that Palmer could make a play like that. Palmer was running around blindly in the pocket on that play expecting to get sacked and he was even running into the backs of his OL. Was just a fluke play.
Also, looking at that play, if Randall didn't do what he did, AZ had a play deep toward that right side anyway. AZ had a WR crossing the field deep toward the right sideline where a well thrown ball was an easy catch. So either way, AZ was most likely going to make a play there.
It was just a damned if you do and damned if you don't situation.
I don't see the Arizona WR crossing the middle open on the right. The defender is right behind him and Randall isn't close to the receiver anyway.