In the original post I theorized that tying the expansion of Hazardous Terrain to the counting down of the Doomsday Clock could be an interesting game variant. For reference, the rules for Exotic Terrain and Environmental Systems are on page 135 of the Rapid Attack rulebook.
In this game I chose the "Roadway Rumble" table-setting
because it was built around baseplates and had a fairly limited
footprint. I chose to start the Hazardous Terrain (HT) on one
baseplate instead of the three in the original post. As there are
12 baseplates we rolled a d12 to determine where the HT started.
At the end of the first Round the Doomsday Clock (DC) ticked down twice
so the HT expanded two baseplates. To make it easier for use, we decided
that the HT would expand in straight lines. There were three possible
baseplates for the HT to expand into so we rolled a d6 to determine
which ones -- 1,2 equals one, 3,4 equals two, and 5,6 equals three.
HT expanded two more baseplates. There were four possible baseplates
for the HT to expand into so we rolled a d8 to determine which ones.
At the end of the third Round the DC ticked down three times so the HT expanded three baseplates for this round. There were 5 possible
baseplates for the HT to expand into. To make it easier we rolled a
d12 to find which ones it didn't expand into. Honestly a d6 would
have been easier and I'm not sure why we didn't think of that.
twice again so the HT expanded two more baseplates.
At the end of the fifth Round the DC ticked down once to
end the game so the HT expanded into the last baseplate.
Which we covered for sake of completeness.
So, to sum up, Choose a set of baseplates, set starting Hazardous Area, determine starting
point, start playing the game, and determine how the Hazardous Terrain expands.