Are military personnel, policemen, or other agents, who are unable to adhere to certain duties such as growing a beard, considered to be in a state of necessity?

The ruling on those in the army and internal security forces who are unable to fulfill some obligations is relative and varies according to circumstances. The fact that someone is a soldier or a police officer does not exempt them from religious responsibility regarding performing duties and avoiding prohibitions. However, they may be permitted some prohibitions when there is a necessity.