Uneven parallelism means that the clauses within your sentence have the same grammatical structure. If you look at the clauses in the sentence "with a keen sense of observation" and "who dedicated long hours in the lab" they do not have the same grammatical structure. Thus the sentence suffers from uneven parallelism.
I believe people do bad things because they have their own problems and want other people to feel like that. Maybe if Carolyn and her husband had a bad past, or something bad happen to them that may be the cause.