Barda needs a diversion
I managed to get my hands on scans from the Justice League Unlimited series that ran for a short while. While thumbing through it, they apparently did special shorts at the end of some of the issues. One of these shorts was one with Mister Miracle and the Slab.
added: This was found in the back of Issue #3 of Justice League Unlimited and the title of the short is "Escape from the Slab".
This is a cute story, but what cracked me up the most was these two panels.