Analyzing Conflict in Dialogue

In a play, dialogue serves not only to convey the plot but also to reveal the characters' personalities, motivations, and relationships. Consider the following excerpt of dialogue taken from a fictional play where two characters, Alex and Jamie, discuss their feelings about a recent conflict:

Alex: I can't believe you went behind my back like that! We were supposed to be a team.

Jamie: But I had no choice! You were being unreasonable, and I needed to step up.

Alex: Step up? Is that what you call betrayal?

Based on this dialogue, which of the following interpretations best captures the relationship between Alex and Jamie?