I was about to point out that in one of the first strips, Belkar got a temporary WIS boost (even though this one will only be half as large, taking him from below average to average instead of above average) that made him not want to be evil anymore, but then it occurred to me:

maybe he'd actually realized how much he needed to fake being a team player, and the healing monologue was for the super-hearing-elf's benefit, until V dispelled it and Belkar forgot to fake it until the LSDream-quest™?