The challenge does not require jumping from the highest point of the facility. The highest point - the large petal array - is probably too far away to make the jump without mods. The solidified lava on the other bank is not sufficient, nor is landing on the raised island in the middle. An Acrobatic Oz Kit makes this much easier, but is not necessary. Players have reported getting the challenge even if the character touches the other side without landing on it before falling into the lava.