For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Jack Gutknecht
Writing on Philippians 1:20 in The Bible Knowledge Commentary (one of my favorite books), my Dallas Theological Seminary professor, Robert P. Lightner said, "Paul's concern was not what would happen to him but what testimony would be left for his Lord. Release would allow him to continue preaching Christ. But martyrdom would also advance the cause of Christ."