This is the second time the writers of “Intelligence” have recycled bad guys from previous episodes. On the plus side, at least they recycled interesting bad guys. On the negative side, this is only episode 12 of season 1.
Villains don’t have to be a one-and-done deal; there’s a right way and a wrong way to weave them into the story.
Right way: write consecutive episodes that utilize the character in a contained story arc. The focus of the arc becomes the hero facing the villain and ultimately defeating him.
Right way: allude to the villain throughout the season. The villain is introduced and temporarily defeated in one episode, but the villain’s nefarious actions are rumored throughout future episodes (perhaps the villain occasionally shows up again in future episodes). This builds tension for the inevitable rematch while keeping the viewer engaged with a story arc that ties the season together.
Wrong way: the villain is introduced and defeated in one episode and just fades into the background never to be mentioned again until that s/he is reintroduced in another episode where they are once again defeated by the hero in one episode.
“Intelligence” chose the wrong way. Mei Chen returns in this cliffhanger episode. They could’ve written her into an awesome end-of-season story covering several episodes and building up to a big finale. They could’ve made her the ultimate season 1 villain, the villain that is continually eluded to, and sometimes encountered, throughout the season. Either way, she could’ve provided a common thread for the season, something this show desperately needs. Instead, they randomly reinserted her into the story without explaining where she’s been or what she’s been doing since she failed to corrupt Gabriel in her last episode (and gets defeated, but isn’t arrested and somehow escapes to who knows where because...reasons?).