Conversation so far:
When did the deposition happen ?
On 13 September, the Parliament held a joint session between the Senate and the Assembly.
What was the joint session about ?
Though several members short of a quorum, they voted to grant Lumumba emergency powers.
Why did gave him emergency powers ?
Parliament did not back Lumumba's dismissal of Kasa-Vubu, creating a constitutional crisis.
How long did the emergency powers lasted ?
On 14 September, a coup d'etat organised by Colonel Mobutu politically incapacitated both Lumumba and Kasa-Vubu.
Did they put him in jail ?
Lumumba was placed under house arrest on the next day at the Prime Minister's residence.

Question: What did he do after the house arrest ?
Self-contained rewrite: What did Patrice Lumumba do after being put on the 15 September house arrest ?