Given that T-bug still lives in one of the hype videos (she hasn't been "made" or has beaten the counter-hackers), that suggests the possibility that she might have been able to hack the AV to try to get them out that way.
They could still have ended up with roughly the same tower/Jackie dying sequence as occurs if you go the ledge route, if the AV is immediately shot down, though. It would make sense to cut that content, however, if they weren't going to go with a "T-bug still alive" route (which presumably would have developed the story another way, with the conjuncture still being back at the No-Tell Motel, but with two potential resolutions there, as per the hype video).
At the end of the day it makes absolutely no sense at all to have the dangling Evelyn Parker request and the dangling bit of Dex suspicion when they're doing the pre-mission briefing, unless at some point there had been at least some kind of plan for an alternative route. I mean, as a player, going by the usual rules of an RPG, playing the game the first time, the Evelyn Parker route seemed like a potential path that I for one was strongly tempted to take, because I was suspicious of Dex on account of Viktor's earlier warning. I was disappointed that it led nowhere, since I'd been teased by it.
It's likely Jackie would have died one way or the other, but if the chip wasn't initially envisaged as leading to the whole V/Johnny scenario, and that was a last year and half shoehorning, then the choice of Dex or Evelyn would have led to different routes analogous to the early choice someone mentioned in TW3 - i.e. not a monumental difference, but enough to give the game a different feel. I suspect that there's a lot of cut content re. Pacifica too, and that would have tied in more with the Evelyn route probably, and that would have likely tied in with a more developed NetWatch (which, again, is offered as a potential major player in one of the hype videos, but is only vestigially involved in the game as is) and a more developed AI story (Peralez, etc.).