I think this is inevitable after tonights episode. She quite definitely wanted him to stop dancing with her, and we all know what happens to people who cross her. Just ask Laurie.
Pam is definitely a lunatic under that bubbly exterior. Her true self comes out when she's frazzled by something. She killed her own son for goodness' sake. No wonder Les is cheating. So much a man can take living with a mad mutton like her.