Basics of vent calculation for reaction runaway control

Why is the reaction mixture drawn into the vent when the reactor is depressurized and a runaway reaction occurs?

Opening the vent at a pressure higher than atmospheric pressure depressurizes the enclosure.

In the case of a system with high vapour pressure, boiling occurs in the liquid mass, whose apparent volume increases until it reaches the level of the emergency vent inlet. The liquid is then drawn into the vent line.

In the case of a hybrid system, the same phenomenon occurs as soon as the liquid starts to boil.

In the case of a reaction system where the pressure results from the production of non-condensable gases, the gases dissolved in...