A more thorough explanation:

Definition: Gantlet (also spelled gauntlet or gantlope) refers to a former military punishment where the offender was forced to run between two rows of soldiers who would lash them as they passed. It can also refer to a series of severe troubles or difficulties, an ordeal.

Examples:

• During the 17th and 18th centuries, gantlet was a common punishment for soldiers who committed serious offenses.
• After losing his job, John had to run the gantlet of finding a new job in a tough economy.

The first example illustrates the historical use of gantlet as a punishment in the military. The second example shows how gantlet can be used metaphorically to describe a difficult situation or challenge that someone must face.