What does lakin accomplish in “Zayd did not come, but Amr did”?

Particles of Meaning: Waw, Fa, Thumma, Bal and Lakin

• Equal affirmation that both Zayd and Amr came
• Reaffirming Zayd’s arrival instead of Amr’s
• Marking Amr’s later arrival after Zayd
• It affirms Amr’s arrival after denying Zayd’s