Sallah: Indy, why does the floor move?
Indiana: Give me your torch. [He drops it in and sees why.] Snakes. Why'd it have to be snakes?
Sallah: Asps. Very dangerous. You go first.
While Indy and Marion are in the Well of Souls, and they encounter the snakes, Indy falls to the ground only to be confronted by a hissing Cobra rearing its head. Look carefully and you'll see the snake's reflection on the safety glass between it and Indy. Briefly you can also see the torch's reflection while he's waving it around. [This has been corrected in the new DVD set. You can only see it if you have the original VHS. I think it's visible in the "making of" on the DVD as well.]