i think i'm gonna go with liz! i'll c&p from above since i'm lazy haha.
i'm still trying to figure her out but basically she's the younger sister of the now recently deceased pilot of paladin V. it's left her a much more subdue version of the cheerful and spunky medic she once was. i think she's been working with A.C.E since she completed her nursing training when she was relatively young. probably around 23ish and she's 30 now, so 7 years. it would make her fairly familiar with the lot of them. she has just always had that instinct and drive to want to help people and that much hasn't changed since her brother died. if anything, it's only made it more prevalent.