Why might ʿAmrun yatakallamu following jāʾa Zaydun be heard as an independent report?

Appendix to Faṣl and Waṣl: Circumstantial Clauses, Wāw and Pronominal Linkage

• Both are imperatives
• ʿAmr cannot be a subject
• The first clause lacks a subject
• The second complete clause lacks an explicit circumstantial link to the prior event