A CS capstone team has been developing a web application for 6 weeks. The four members (Emma, David, Lisa, Marcus) are now experiencing significant tensions.

Current Behaviors:

• David openly challenges Emma's React choice: "Vue would be much better for this project"
• Lisa sides with David, creating a 2v2 split with Marcus supporting Emma
• Team members interrupt each other during technical discussions
• Personal criticism emerges: "You always overcomplicate things"
• Subgroups form - David and Lisa meet separately to plan their approach
• Productivity has dropped as members avoid collaboration
• Marcus struggles to maintain authority as project manager
• Everyone has strong opinions but little willingness to compromise

Which stage of Tuckman's team development model does this scenario represent?