It would be a rather unique situation. If he walks out of the gate to go to a session, I believe this would apply.
They shall in all Cases, except Treason, Felony and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same; and for any Speech or Debate in either House, they shall not be questioned in any other Place
At least it would be a strong argument for a furlough.
Uhhh...wasn't Traficant convicted on felony charges?