I won't lie, i never manage to blew up myrellion, didn't know you could do it actually (i know you can destroy tarkus, but didn't for myrellion) so i can't really help, somebody else might know tho.
You can only blow up Myrellion if you have a hard/mischevious personality and its during the second Kara Quest when rig the pirate ship to blow up. If you hover over the options it'll tell you the plant will go down as well. Its a complete waste though unless you hate ants, you can only visit the caverns if the planet is destroyed.it is became nuclear wasteland?
wtf?
idk what happened?
Just go to the TITS save editor and delete the relevant flags
"Change kq2_Myrellion_State to 0. You might need to also set kq2_Nuke_Started and kq2_WatsonSelfDestruct to 0"