DD of Chain Reaction Q (help pls!)

I ran the Normal Lab maybe 30 times and used the option "get a gem from the same color." So far, not a single Detonate Dead of any kind. Is this just bad luck or is the gem locked behind a higher tier lab? I am asking because the 4th lab is kinda slow and seems not worth it for just 2 more options that are complete crap.

Bad luck.

I'm on run #80 or something and haven't seen it.

Yuck. The initial changes in the lab trials was to prevent RNG block characters from progressing. With the difficulty of targeting gems, the issue is back.

same here. Spent 4 days already .. initially farmed from Merc Lab and yesterday tried to farm Norm Lab to do it faster. got all kind of transfigured gems, but no DD of chain reaction or any other DD yet. I'm not getting any XP anymore too. is there a specific type of green spell gems, that I should use to transfigure that would increase my chances of getting of DD gems of chain reaction?