Weres nina sharp gone?
She's in it. In an interview with Georgina Haig or Anna Torv she says how they are all young because of the amber but Boyles and Nina have aged which I think is a pretty big hint that Nina will come back.
Also we saw Massive Dynamic being anti-mattered, this I think gives a big hint to what someone earlier in this thread thought...which is that stuff that is anti-mattered can come back, i.e. Massive Dynamic can come back and Etta won't be dead permanently. I certainly hope this is the case anyway.