If we reach the end of combat and a party member is down, I think the game should stay in turn-based mode until the downed character is revived or the player chooses to go back to real time. A couple of times, I've had characters die while I was looking over my abilities deciding what I want to use to bring them back up. In a tabletop setting, even if a DM is pushing you to act, you'll generally get more than 6 or 12 seconds to decide on a spell and cast it.
