Conversation so far:
What was Hekmatyar's relations with the Taliban?
The Pakistani military had supported Hekmatyar until then in the hope of installing a Pashtun-dominated government in Kabul, which would be friendly to their interests.
Did Pakistani military install the Pashtun dominated government?
By 1994, it had become clear that Hekmatyar would never achieve this.
What did the Pakistanis do about installing the Pashtun government?
Pakistanis began turning towards the predominantly Pashtun Taliban.
What happened after the Pakistanis turned towards the Pashtun taliban?
After capturing Kandahar in November 1994, the Taliban made rapid progress towards Kabul.
What were the Taliban going to do with Kabul?
The Taliban were making inroads into Hezb-i Islami positions.
What did Gulbuddin Hekmatyar do in Surobi?
On 14 February, Gulbuddin Hekmatyar was forced to abandon his headquarters at Charasiab, from where rockets were fired at Kabul, and flee in disorder to Surobi.

Question: how long did he stay prime minister?
Self-contained rewrite: How long did Gulbuddin Hekmatyar stay as Prime Minister?