Hoo boy, this is a hard one for me since I run like 5 characters? But my main one is Ensign Frank 'Ocelot" Stumpling, Intelligence Officer.
Were he to die in the first contact/expected contact scenario, he'd pretty much die like it always happens. Dying for intel. As he makes his way down on those DEFCON levels, the pressure is higher and higher and the moment where you realise intel is scarcer and scarcer, there are no more data terminals surrounding the safe haven of a Landing Zone, it is the moment you know you have to go in deep. Like always, he tells the marines that escort him that "the document pouch is important". Deaths can happen in many way here.
Should he actually succeed and, well, survive, I think that Ocelot would be the type of character that would try to use all of his knowledge regarding xenos to further it and possibly prevent other catastrophes like the one he had been through.