Ramikad

Somehow I was expecting an answer more like this:

http://www.reactiongifs.us/wp-content/uploads/2013/11/magic_motha_fucka_your_highness.gif

But yeah, you have a point.

Apparently the DVD commentary explains that detail; Rick McCallum : This blue light around the bottom of the light and the platforms was added later on, in Production. George felt that at one point, that we needed to feel that there was some cooling effect, some kind of shield...a reason why our actors aren't burning up being around this intense heat so Roger Guyett and his team added these shields, this shield generator into this shots as another pass after they'd completed a lot of...

these shots...to help tell that story of the cooling.