Never be discouraged if someone suddenly wants to terminate a witnessing conversation. Paul's conversation with Felix the Governor was suddenly terminated. Felix said, "Go your way..." The Bible tells us why Felix did that. He was trembling. The Law has that effect on those that are guilty. Paul reasoned about righteousness (which is of the Law) and judgment (which is by the Law). He spoke about "temperance," and the guilty governor tremble and terminated the conversation. The Apostle may not have seen him trembling, and been disheartened. So never be discouraged when a conversation suddenly ends. Agitation or anger is a good sign that something is going on in the heart. Don't give up on the person. Use the secret weapon of closet prayer. God can continue speaking to him, even if you can't. There goes another minute. Gone forever. Go share your faith while you still have time.