Distance and scope. Hopefully, I got this right. Tell me if I'm talking bullshit though. It's quite likely, since I'm out of coffee.
First person:
I gripped the steering wheel so hard that my nails dug into my palms hard enough to draw blood, but the pain barely registered.
Screw Chad. He was going to get what was coming to him. I glanced at the bag. Good. The gun wasn't showing.
Third person limited (close):
Karen gripped the steering wheel so hard that her nails dug into her palm. The welling blood and subsequent pain barely registered.
Screw Chad. He was going to get what was coming to him. She glanced at the bag. Good. The gun wasn't showing.
Third person limited (middle distance):
Karen gripped the steering wheel so hard that her nails dug into her palm and were causing blood to well up, but Karen barely registered it.
Screw Chad, she thought. She was going to make sure he got what was coming to him. She glanced at the bag and smiled.
Third person limited (distant):
Karen's fingers were tightly wound around the steering wheel. Her nails were red with blood, but she didn't register the pain. She muttered a curse under her breath, and quickly glanced at her bag to check if the gun was visible.
Add some omniscience:
A few people gave her car mildly interested looks, curious at how fast it was going.
(Italics added, just to please
@Stuart Dren)