After the Boss fight where you fight Paul, he will be engulfed in flames. Do not kill him. Instead, pick up the fire extinguisher in the store to put out the fire. Then, bring Paul back to the security room. If done correctly, there may be two women as well. After a while, you will receive a call saying that Paul has a present for you. Go back to the security room to meet Paul. Continue to talk to him and he will give you an unlimited supply of Molotov Cocktails.