Batman states "both" Green Lanterns are off-world, but we've already seen Hal Jordan, John Stewart, and Guy Gardner as ring-slingers.
Wally says the fight with Vandal Savage took 15 minutes, and this is supported by the countdown timer on his wrist pad; however, we saw the entire encounter on-screen, and the fight actually only took 2:19.
When Wally arrives at the Seattle hospital, we see a gowned patient, pushing an IV, walking through the lobby. A patient in this condition would not be allowed out of his treatment area.