A mechanical whir. The organic crack of wood being split by metal. The rhythm thud of feet on concrete. A robotic 'head' peers into the room.
"Drop your weapons. You are surrounded."
Not fiction, but a genuine training drill that the US Marine Corps Warfighting Lab and employees of the Defense Advanced Research Projects Agency (DARPA) are carrying out with Spot, a quadruped prototype robot.
Spot is a dog - a 72 kilo robotic dog made by the Alphabet-owned Boston Dynamics. Controlled by a radio link from a laptop computer and an Xbox 360 controller from a range of 500 metres, the US military is actively exploring just how they can use robots like Spot in the field. Boston Dynamics has said that the system is so simple, children as young as four are able to control the robot.
"The Marines have been very receptive to the new technology, embrace it and come up with new ideas we couldn’t even dream up," said Capt. James Pineiro, the branch head for Marine Corps Warfighting Lab. "Spot is great and has exceeded the metrics that we’ve provided. We see it as a great potential for the future dismounted infantry."
By sending Spot into a potential hostile environment, such as an occupied building, the Marines are able to scope out potential hostiles, trigger traps and keep live personnel out harms way.
But this isn't a finished model - Spot is just a taste of things to come.
"We continue to invest in research and development of robotics and autonomy to find ways to reduce threat to Marines and enhance our capability at the same time," said Pineiro.
Who knows - the next version of Spot might be carrying its own gun.
Take a closer look at Spot below.