Revealing mistake: When the plane goes through the smoke at the start, the smoke doesn't react in any way - it keeps rising. Surely the wind from the plane would make the smoke drift a different way. (00:12:25)
Revealing mistake: Just the bridge is blown up at the start, you can see all the soldiers have been replaced by dummies. (00:12:10)
Answer: The words of their chant are "Beware, beware, walk with care. Careful what you do. Or Mumbo Jumbo's gonna hoo-doo you. Mumbo Jumbo's gonna hoo-doo you. Boomlay, boomlay, boomlay, boom!" This comes directly from a poem titled "The Congo" by poet Nicholas Vachel Lindsay ("The Congo and Other Poems"), specifically the lines at the end of part I.
Super Grover