All the little (or not so little) psychoses and neuroses that we spend a lifetime amassing, are the undercurrents running beneath our daily lives today -the baggage, so to speak, that we must carry- which is why Tranquilla needs the bag she's carrying -out of sight, out of mind- hence the serene expression on her face.
My mother used to call a bag like this a 'grip' -maybe somebody told Tranquilla to "get a grip", and old fashioned girl that she is, took it literally.