I have to admit that the formaldehyde thing troubles me. Why does Randy carry such a small quantity of it? If Randy is linked to Raydon Labs and somehow managed to remain some of his intelligence, why does he transport it in such an amateurish way? I mean, there are some quite explicit transportation guidelines such as http://water.usgs.gov/admin/memo/pol...icy93.044.html. So, Randy's health might have slightly deteriorated since we last saw him.

Nevertheless, thin foil time: maybe the formaldehyde solution is used by TWOWTM as a carrier as part of a catalyst chain process to create his special zombies. Pure speculation.