I think it’s part of the plan, such as it is. All anybody monitoring would see (if they were paying attention) is Chewie breaking loose. Then Han gets on the intercom to further delay anybody coming up to investigate. Some of those greeblies being shot at on the walls always struck me as wall lasers or possibly tear gas vents some kind.

It seems to have a moveable central eye.

Even if Han having served in the Empire isn’t in the back of George’s mind at that point, Solo would know what to take out first in attempting a jailbreak.

The comic book clearly explains they’re pretending to shoot at Chewie while blowing up the cameras and such.