bodyguard a group of men who escort and protect some important person
patrol the activity of going around or through an area at regular intervals for security purposes
picket a form of military punishment used by the British in the late 17th century in which a soldier was forced to stand on one foot on a pointed stake
press gang a detachment empowered to force civilians to serve in the army or navy
provost guard a detachment under the command of a provost marshall
rearguard a detachment assigned to protect the rear of a (retreating) military body
detachment -
the act of releasing from an attachment or connection
detachment -
Any smaller portion of a main body separately employed.
Wikipedia
Detachment, also expressed as non-attachment, is a state in which a person overcomes his or her attachment to desire for things, people or concepts of the world and thus attains a heightened perspective.