A common situation is for one survivor to be incap'd while another is standing by defending them, waiting for the right time to help them to their feet. When this happens, the SI team tries hard to incap the remaining survivor.
One thing that can be of great advantage in this situation is the fact that a survivor's hitbox doesn't seem to change when they are incapacitated. We've all had that frustration as hunter, where you go for the standing guy, only to pounce on the already downed guy!
Use this to your advantage: sand behind a downed teammate, keeping them between you and the likely direction of a pounce - any hunter-attacks aimed at you will instead hit your incap'd friend; where you can then kill them safely and easily before reviving.
I do this all the time. Exploit perhaps? In fact, lots of people use the extra incap hp to prioritize what they need to be doing. There are pros and cons however, for example, this makes it easier to pounce a incap whos close to dying.