Remember lancer petrified quickly in the cyber world but in the tv world it took as long as the zapper from catty’s house and ramb (who originally came from the cyber world) well i think because lancer kind of belonged there at kris and toriel’s home since playing cards are often used at home for game nights and stuff

ANOTHER THEORY

I think deltarune chapter 5 will take one half of the chapter in the flower king dark world AND the festival (the flower king dark world acting like a distraction for the gang) and the festival will be the actual final boss erea for chapter 5 as asgore was a fake out for the final boss of chapter 5

Because i just mentioned lancer didnt quickly petrify because cards kind of belong at home, well i can see the same happening to jevil at the carnival dark world and playing cards are also part of magician tricks wich also are part of carnivals so i think jevil belongs there aswell having a connection to a major character in the festival dark world