I don't think these are "pets". These are wild tokays in their native habitat which includes people's homes in se asia- in this case thailand. Homes in this part of the world are often not very lizard or snake proof.
I also guess you guys are correct- the geckos are seeing the movement of the snake and trying to eat it. I kind of doubt one is trying to save the other. One has the snake in a hold, the snake has been taken from someplace where it had a grip. The other sees the snake wriggling a bit and tries a sample as well.