TOS-r: Friday's Child
Put Your New Regular Character in a Scene Even Though He Has No Lines Department:
In the teaser, Chekov is sitting in on the briefing about how dangerous the Capellans are, though he has nothing to do except sit, listen, and exit. He doesn't even get a 2 second reaction close up. He is not part of the landing party.
Naturally security guard Grant, who is not given this warning, reacts to a potentially hostile situation and is immediately killed.
When it would make more sense for Grant to be in the briefing, get your new teen-oriented character in the scene instead and don't give him anything to say.