What is the purpose of rupture disc

Explain the function of a rupture disc

In this image we can see the use of rupture disc, so If the Bourdon tube is punctured this Rupture Disc breaks.

Rupture disc, primarily intended for the safety of Gauge, when Bourdon tube is punctured and pressure Building up in Gauge, before breaking the glass, the build-up pressure would escape through this Rupture disc.