When they leave a night shift and have to walk to the edge of the hospital parking lot, they hold the vial in one hand.
Dropping the vial breaks the glass and emits an aroma several times more offensive than ou de skunk, detering most criminals and providing a physical erection barrier to rapists.
Sounds like a product I've seen at some of the places that sell pepper spray and stun guns, called "REPULSE Rape Deterrent". This stuff supposedly creates a truly appalling stench that has to be removed with an *antidote*.