Apprehension or Fear
Also known as Immersion Syndrome or trench foot it was common among World War I troops. They would often spend long periods standing around in the trenches filled with cold and muddy water.
It was very painful, but also guaranteed a trip to hospital. Those who didn’t want to be shot at would endure the pain until just before a major offensive, reporting to the hospital at the last minute.
The first documentation of the condition can be traced back to the Napoleonic Wars.