Conversation so far:
When did Thabo Mbeki arrive in Lusaka?
Mbeki left London for Lusaka in April 1971.
Why did he go to Lusaka?
to take up the position of assistant secretary of the ANC's Revolutionary Council (RC).
Did he enjoy his time in Lusaka?
CANNOTANSWER.
What was his mission in Lusaka?
Mbeki travelled to Beichlingen to deliver a speech on behalf of the ANC's Executive Committee at the YSS summer school.
What did he do while there?
This was a turning point in Mbeki's life as it was the first time he spoke on behalf of the ANC as opposed to the ANC Youth League.

Question: What was a career highlight while he was in Lusaka?
Self-contained rewrite: What was Thabo Mbek's career highlight while in Lusaka?