Several of the comments here are helping me see my characters through others' eyes. I definitely wanted to give Pam layers although perhaps I've made her too sympathetic. Having been in situations where someone was acting unfairly - unjustifiably hostile - I've wondered what makes someone hateful and angry? Hence, the birth of the character of Pam. In allowing her third person narrative to come forward, I wanted to explain - at least to the reader - the origins of her hostility: money and relationship problems at home, almost a decade of work ambition thwarted by an obtuse CEO. Accordingly, she had emotions and reactions with which anyone can identify; and this can surely make us feel sorry for her.
Pam, however, chose to let her hate and anger take over which was, ultimately, her undoing. As mentioned in this discussion, many of us have known someone like Pam, but what differentiates us from them, is how we deal with what is going on in our lives. Do we take our anger out on other people? Or blame the innocent for our lot in life? Do we roll with the punches or focus on what didn't go as planned? Pam had such disregard for the feelings of her team because they were simply standing in the way of her ambition. She was blind to their own motivations; Elaine's in particular. The choices Pam then made are what led to her downfall.
On the flip side, my intention was not to make Elaine come across as either sneaky or underhanded. Instead, I needed her to bide her time and gain Pam's trust (or least allay Pam's suspicions). Her allegiance, from the first, was always to her paycheque and the anonymous client to whom she was selling the company's secrets. I made Elaine an observer at first, on purpose. She was on the receiving end of Pam's malice but indirectly. Elaine needed to be powerful, but not overtly so. Also, despite her competence and intelligence, she was powerless to do anything about Pam - as is the situation of many employees under a bullying boss. And so, Elaine waited and watched until the perfect time to finish her own work while also, finally, being able to exact justice for her team.