The fact that Goro may be intruding or that his presence would be unwelcome literally never even enters the Shokan's head. Something interesting is happening with combat applications. Who wouldn't be intrigued by that?

When Diana nods and gestures towards the weapons, Goro walks over and takes a spear in one of his upper arms. It looks comically undersized in his massive fist, but he leans in, examining the spear more closely. "Yes. I see a mark." It's not far down from the speartip.

Magically-imbued weapons, hm? Turning, Goro flips the spear around in his hand to a throwing position, then aims it at one of the dummies. With a flick of his elbow, he hurls it, driving the spear into the dummy's midsection, curious to see what Diana's magic has done to it.