Heller anticipated that viewers would eliminate suspects one by one as they are being featured in each shows. So he plays a game and features McAllister early and uses a dramatic moment where the sheriff rescues PJ from a tall height. Viewers conclude he cannot be the suspect because RJ is afraid of heights and because he rescues PJ.

However,.....

Heller has assured us that it is one of the 7 (well, now 5)

RJ could easily have PJ dead but keeps him alive. So too does McAllister with his rescue
RJ would not show the outward antagonism towards PJ that Stiles, Haffner, Smith and Bertram. The only suspect that seems to be friendly with Janes is McAllister
A hillbilly Sheriff seems so distant to a sophisticate like RJ but that's what makes it interesting
We have been 'conditioned' to hate the Visualize cult so anyone associated with it is unlikely to be the 'real' RJ
Stiles is missing so he is too obviously being dangled as a 'likely' subject
Bertram is too uninteresting a choice since he would the be tangled up in the banal 'conspiracy at the CBI top' and this might disappoint viewers. Bertram, Haffner can then be crossed off