Apparently the Dutch stage adaption differs a bit compared to the Broadway version, but I'll explain what the Dutch one is like....
The audience is let into the hall and the doors are closed. The lights are not yet dimmed, so everyone is still watching around to see all the green stuff and the nice Tarzan-things
Then, all of a sudden, lights go out, you hear thunder and the lights imitate lightning, which is really cool. You see a decor with on the top the blue sea and at the bottom the beach colours. Tarzan's parents float against this decor trying to "swim" (they make swimming movements) to the coast, so a little lower. The ropes that they're attached to let them go to the beach. Then they get safely downstairs/on the beach and you see the hut in the tree and Tarzan and his parents are there.
The leopard jumps out of the side and lands on the hut, where struggling a bit with the parents (you can not see this, the lights are flickering in this bit). Then you only see little Tarzan crying.
The hut disappears and you see Korchak and Kala with their child and several other gorrila's. Then the leopard comes here as well and fights with them, Kala remains crying. Then you hear the baby Tarzan crying and Kala goes looking for it. She finds it and Korchak disapproves it. Kala wants to care for the baby and sings You'll Be In My Heart.
I hope it's a bit clear like this?