Context : The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss rate/geometry and therefore knowing the geometry of the circumstellar material close to the star and its surroundings is crucial .

Aims : We aim to give an insight regarding the nature ( i.e .
geometry , rates ) of mass-loss episodes , and in particular the connection between the observed asymmetries due to the mass lost in a fast wind , or during a previous , prodigious mass-losing phase .
In this context , yellow hypergiants offer a good opportunity to study mass-loss events .

Methods : We analyse a large set of optical/near-infrared data , in spectroscopic and photometric ( X-shooter/VLT ) , spectropolarimetric ( ISIS/WHT ) , and interferometric GRAVITY-AMBER/VLTI ) modes , toward the yellow hypergiant IRAS 17163-3907 .
We use the optical observations to determine its spectral type and we present the first model independent reconstructed images of IRAS 17163-3907 at these wavelengths tracing milli-arcsecond scales .
Lastly , we apply a 2D radiative transfer model to fit the dereddened photometry and the radial profiles of published diffraction limited VISIR images at 8.59 \mu m , 11.85 \mu m and 12.81 \mu m simultaneously , adopting a revised distance determination using the new Gaia measurements ( DR2 ) .

Results : The interferometric observables around the 2 \mu m window towards IRAS 17163-3907 show that the Br \gamma emission appears to be more extended and asymmetric than the Na i and the continuum emission .
In addition , Br \gamma shows variability in a time interval of four months , not seen towards Na i .
Lastly , in addition to the two known shells surrounding IRAS 17163-3907 we report on the existence of a third hot inner shell with a maximum dynamical age of only 30 yr .

Conclusions : The interpretation of the presence of Na i emission at closer distances to the star compared to Br \gamma has been a challenge in various studies .
To address this , we examine several scenarios , and we argue that the presence of a pseudophotosphere which was traditionally considered to be the prominent explanation is not needed , but it is rather an optical depth effect .
The three observed distinct mass-loss episodes are characterised by different mass-loss rates and can inform the theories on mass-loss mechanisms , which is a topic still under debate both in theory and observations .
We discuss these in the context of photospheric pulsations and wind bi-stability mechanisms .