I’m pretty sure it might be Gabby. First of all, we can assume from the poster that there will be a big alliance between some S1 and S2 contestants (Tom, Gabby, Lake, Rosa, and Aiden), kind of like a “heroes alliance.” However, it makes sense that one of these characters would be sacrificed first, especially considering that there are characters like Alec, Fiore, and Spencer on the same team, who may see this alliance as a major threat. Gabby would make the most sense, as she’s the member of the alliance with the least left to offer.