Alan Kertz the Senior Gameplay Designer on Battlefield 3 has revealed that on Battlefield 3 it will be possible to kill someone who’s being revived.
When Kertz was asked if it was possible to “kill someone while a Medic is reviving them” he replied “Yes, yes you can kill a guy who’s just been revived.” This will obviously remove the annoyance caused by the “god mode” players used to receive from being revived.
While it probably won’t help the person being double killed at least a seemingly dead opponent isn’t going to get the advantage over you.