Head Start frustrations

So I went out to Head Start on Thursday afternoon to present a ST. Trouble started with my arrival; the director informed me that a police officer was scheduled at the same time (unapologetically), and asked me to wait and do the ST afterwards. Uh, ok, I said. In the cop's defense, he was pretty good with the kids (he successfully got them off questions about his gun, finally) and didn't go too terribly long (about 20 minutes). Still, a tough act to follow, because 1) the kids had already been sitting still and listening for 20 minutes and 2) I don't have a gun or walkie-talkie or badge.

I knew I'd have to do a pretty interactive, lively ST for the increasingly squirrely kids, and I tried, but a major cause of annoyance (sounds bad, I know) was a boy with developmental delays/mental challenges. He roamed all over the room during the ST, including walking between me and the seated kids, playing with toys in the room, and sprawling/rolling all over a caregiver seated at the front, just to my left. And the caregivers? For the most part, they were content to just sit and watch as the boy did whatever. Which would have been tolerable, if the other kids hadn't frequently done the same. In other words, the seated kids (about 30 of 'em) were definitely distracted from the books and stretchers I was trying to present.

This was a tough situation because I knew it was totally unfair to blame the boy, and I wasn't really sure what exactly the caregivers should do. I do believe in inclusion, and I really tried to establish eye contact, speak directly to, and otherwise engage the boy, but he was not seeming to pay any attention at all, or have any interest in the ST. At one point, a caregiver did try to hold him on her lap, but he started squirming and making loud noises, so she let him go, to walk around the room again, relatively quietly.

I'm still not really sure what to do or say to help the situation, for next time.

Thoughts?