I was wondering why Gazelle (assistant of Valentine) in Kingsman: The Secret Service didn't die or her head didn't pop out when Merlin detonates the security chips whereas it was shown in some part of the movie that Gazelle has a scar on her neck that proves that Valentine put a security chip into it. I think the part where the scar was shown is when Valentine was introducing his newly invented sim card in the expo.
The woman at Valentine's press conference (where they notice that she has an implant) is actually not Gazelle but some other assistent of him, who I'd wager wasn't as close/important as Gazelle to warrant an exception from the implant. As you can see, she has a significantly different face and haircut (which Gazelle never changes throughout the movie):
In fact, we see her again at other points throughout the movie. For example, when Harry sees her carry the invitation for the church event while visiting Valentine at home (where he also sees Gazelle, so they can't be one and the same person). Another point is when Eggsy is greeted by her when arriving at Valentine's base and hands her his weapons.