Bliss+Tmux: no message if beacon is not running

in case beacon is not running

without tmux

$ TANGO_HOST=localhost:20000 bliss --no-tmux
!!! === RuntimeError: Could not find any conductor (check Beacon server and BEACON_HOST environment variable) === !!! ( for more details type cmd 'last_error' )

with tmux

$ TANGO_HOST=localhost:20000 bliss
Starting new tmux session __DEFAULT__...
[exited]

Can we display the error message outside of tmux in case bliss crashes?