iPhone 5 iOS7: Prevent screen from locking during voice call This seems like a simple feature that must exist, yet I can't find it in settings or by googling.  I want this behavior:

The screen should never lock while I'm on a voice call, no matter how long I'm talking.  

After the call is over, it should return to its normal behavior, locking after X minutes of inactivity or when I click the top button to turn the screen off.

Can this be achieved?
This bugged me for a while. I just found out that (on my phone anyway) if you slide your finger from left to right on the name of the caller, you will see your call menu again.