In military terms, triage is a system whereby
casualties are prioritised according to the
cost-effectiveness of treating them; in this case, 'cost' means 'military usefulness'. The wounded are divided up into four groups - 'minimal', 'delayed', 'immediate' or 'expectant'. Those who can be treated and sent back to
the lines quickly are 'minimal'; those who do not need immediate treatment but are combat-ineffective are 'delayed'. If you are a casualty, this is the best place to be).
The other two categories are similar. Those who require immediate, life-saving assistance are 'immediate', whilst those who are beyond help are 'expectant'. Without proper treatment the former can easily become the latter. Expectant cases do not receive treatment, as they eventually cure themselves, although they are periodically reviewed to see if they have fought off the clutches of death, and thus many books about war mention wounded soliders waking up amongst piles of corpses, and scaring orderlies.
As an aside, the US Army's 'Field Manual No. 8-51: Combat Stress Control in a Theater of Operations' contains the following, pithy comment, which suggests that whatever happens, never lose your weapon:
"It should always be remembered that a small number of neuropyschiatric cases may have weapons and be so potentially dangerous that they deserve the highest priority for management regardless of the type of triage being conducted."