Difficult behaviors often work for people because the behaviors catch us off guard and we freeze (e.g., your brain starts racing and you think, Did she really just say that?) and/or we get so uncomfortable that we do whatever it takes to end the interaction.
Instead, try the opposite: Show that you’re aware of and unrattled by what’s going on — and unwilling to go along with it.
Strive for calm, neutral observations starting with “I’ve noticed that ...“ Focus on the behavior, not the person: “Niko, I’ve noticed that you’ve interrupted me a few times. I understand you’re upset. Could you give me a few minutes to share my perspective?”