It is worth remembering that the Boston Marathon bombers armed their pressure cooker bombs with the insides of fireworks.
Maybe a sales clerk who sold the pressure cooker left female DNA on what would become a Boston bomb.
When pressure cooker is finished, allow the pressure to release naturally.
: flung into the pressure-cooker existence of live TVnoun phrase
A place or situation of great personal stress: the pressure cooker on the Hudson (1958+)