A Porcupines quills can become detached when touched or when stuck inside a person however Porcupines are not able to shoot out their quills like some people used to think.
Although A Porcupine cannot shoot it's quills out at your or an animal the porcupine can kill someone or an animal if they stab them with the quills.
So avoid Porcupines if you come near one or more.