Nug science is the way of the future in Thedas. As usual, dwarves are ahead of the curve.
I doubt she personally called her in, it's implied that she's already in the castle when Alexius uses the amulet against us, and gets captured along with Fiona and our companions after we disappear. It's actually why I kept thinking that maybe the Warden was still alive somewhere, that they were just too far away to hear Corypheus' Calling, find out what was happening and get to Redcliffe within a year. But the Venatori who are torturing Leliana right before we enter her cell do tell her "There's no one left for you to protect", so... 
Yeah, the problem with that is that that part of the story makes absolutely no sense.
When the Herald and Dorian get whisked away, that changes very little in the present. Either way, two companions, Leliana, and a bunch of Inquisition agents have got Alexius and Felix cornered, and all of their Venatori are dead, and Felix isn't on Alexius' side anyway. Frankly, I'm shocked that Alexius survives that fight. The real issue is that the Herald isn't there anymore, so the Herald can't close rifts or the Breach, which means that Corypheus and his templar army should steamroll all opposition. That's why the Dark Future occurs - it's
not because the Herald's mission to Redcliffe fails, because it's kind of ridiculous that it might. Bizarrely, this actually comes up in the mission, with Companion B's talk of an assassinated empress and the (Wardens') demon army being the key things.
Which is why, to make that work, I headcanon that the Inquisition finishes off the Venatori and puts what's left of them and the mages under lock and key while Lels calls for backup, then there's a big fight with Corypheus, then 'that thing that I talked about' happens, then Corypheus wins and imprisons people in Redcliffe Castle while freeing Alexius and his goons who get carte blanche to take any mage 'volunteers'. It can't account for everything in the game (like Sera's allusions to a fight after the Herald and Dorian vanish, or the fact that the only prisoners are your two companions plus Lels and Fiona i.e. the people that were there the first time), but nothing satisfactorily accounts for everything in the game. The time travel plotline has some problems.
For what it's worth, I prefer "Champions of the Just"
as a mission; it doesn't introduce any of the time travel, it gives us Ser Barris the Badass, it gives Cole a much more interesting introduction than otherwise, and the Fade sequence with Envy feel (for lack of a better phrase) like "
Dragon Age". And it doesn't have mai waifu getting horribly disfigured and tortured and widowed.
That's kind of why I preferred the Wardens not being able to avoid the Calling. It might be tragic as hell, particularly with Leliana left behind, but I was rather fond of my pre-DAI head canon about the Warden going out like a Viking at Ragnarok in the Deep Roads.
The Calling + female Wardens is the stupidest most disgusting thing. "lol hai darkspawn want some moar broodmothers? MERRY WINTERSEND"