Except if you use VCE you don't have ifRandomDice. You have
onActivate>self>VCE_modVariable>"Client","VAR","Set","1".
onActivate>self>VCE_modVariable>"Client","VAR","RandomNum","2".
onActivate>self>VCE_ifValue>"<var:client:VAR>","equals","1""3 4".
(This would be a 1/2 chance of occurring)
I added some more stuff, including a second floor and double the lava plume areas. I tried to make it so every so often a shower of fireballs would shoot up from below and take out a few tiles, but I can't do that without brick damage on and if it's on, people can blow up the walls and get out. I also tried to take Destiny's suggestion to make a fireball that slowly follows people, but I couldn't make it slow enough. I'll get some new pictures up soon.