After a building collapse, explosion, earthquake, industrial accident, or other major incident, the first problem is often not rescue itself. It is uncertainty.
Responders may not know which routes remain passable, whether floors or stairwells are stable, where hazardous materials are present, whether communications work inside the structure, or what lies beyond the point where personnel can safely see. Yet every decision that follows depends on answering those questions quickly.

A perimeter alarm sounds at 2:10 a.m. The alert tells the security team where something happened, but not necessarily what happened. It could be a person at the fence, wildlife, damaged infrastructure, debris, a failed sensor, or something that requires an immediate response. The traditional next step may be to send personnel or a vehicle to investigate.

Modern military robotics is moving beyond the idea of a machine that simply replaces a person. The more useful question is what an unmanned system can do before a person has to go there, especially when terrain is difficult, information is incomplete, or the consequences of being first are high. That is where quadruped robots become particularly interesting.

In a radiological environment, sometimes the most useful thing a robot can do is simple: go where you would rather not send a person.
Imagine an abnormal radiation reading inside a facility. Before a technician enters, a quadruped robot equipped with the appropriate detector could be sent ahead to take readings at multiple locations and return that data to the team outside. It could approach the suspected source, stop at predetermined points, collect measurements, and provide cameras and other sensors with a view of the surrounding environment. The team now has information it did not have before anyone makes a decision about human entry.

An inspection usually starts with a person going somewhere.
Someone walks the site. Climbs the stairs. Checks the equipment. Investigates an alarm. Looks for heat, leakage, damage, corrosion, movement, or something that simply does not look the way it did yesterday.

On a modern battlefield, GPS is enormously useful. It is also something the warfighter cannot assume will always be available.
Buildings, terrain, tunnels, and subterranean spaces can block or degrade satellite signals. In a contested environment, an adversary may deliberately jam or spoof them. The Department of Defense has publicly described GPS and unmanned systems as targets of electromagnetic interference, while the Army has documented the operational consequences of losing GPS during unmanned ISR missions.