You can use script and mkfifo to allow a second session to supervise the first using this very simple hack.
# on 1st terminal
script -f /tmp/session
# on 2nd terminal
Now the 2nd terminal can interactively watch whatever is going on with the 1st terminal. Occasionally some control characters will get a little garbled when a lot of curses activity is going on, but in general, it works pretty well.