From the onset, Ryou tried to steer the team. Ryou repeatedly moved to block Aoka by cutting her off mid-sentence or ridiculing her ideas. When her proposals were moved onto the table, he would rally for vetoes and pressure the reluctant underclassmen to follow his lead. He would then attempt to rouse the other members (especially the other senior, Kaori) for submissions— whenever he wasn't pushing his own designs onto the table.
Aoka was initially patient, perhaps oblivious, to Ryou's opposition. She eventually came to realize his hostility after multiple proposals fell flat. She then ousted Ryou angrily from his influential podium, verbally reprimanding his subversive behavior, and forced the caucus to accept a general theme for the shirt design. Ryou fumed and sulked for the remainder of the meeting, and the next.
For the large part, the convening members chose to tiptoe around the feud. Before the confrontation, most members complied to Ryou's forceful demands, or found an excuse to avoid it. Afterwards, most of us chose to ignore Ryou, as he remained quiet and began playing truant. Aoka did not seek further conflicts, and carried business on normally.
Ultimately, the conflict came to a breaking point. As we approached making a decision between several drafts, the club supervisor, Hana, came to inform us that Ryou had asked to transfer him to a different task, due to Aoka being "unbearably uncooperative and indecisive." Trusting Aoka more, she came to inquire what had happened. When she was met with avoided glances and Aoka's calm explanation that Ryou was at fault, Hana let the topic drop, and concluded that we were too far along to reassign another senior representative, and briefly reminded us of the deadline before leaving.
In hindsight, there was something everyone could have done to prevent the fallout. Ryou could have chosen to be more communicate in a clear and civil manner, rather than assume his righteousness and everyone else's allegiance. For her part, Aoka could have been more accommodating of Ryou's wants. Instead of letting her frustration swell up and burst, she could have attempted to meet Ryou halfway on issues. For the rest of us, our submissive attitude played a large part into giving Ryou the momentum to corner Aoka, which inevitably led to her retaliation. If we had been a little more firm and resistant to Ryou's pressure, he might not have made the assumptions he did and potentially cause him to refocus his attention on a more generalized, diplomatic approach.