My (29f) BF (30m) left the front door open. My dog got out and was hit by a car. BF didn't apologize.

This afternoon, I was in another room and heard my boyfriend come in. Moments later I heard him yelling at my dog then a loud yelp. I ran to the front room to find that my dog had been hit by a car. Apparently BF was carrying stuff in and didn't close the door all the way in between trips. Dog let himself out and ran into the street.
We ran the dog to the vet immediately. We were very very fortunate that there weren't serious injuries. Dog is expected to make a full recovery. Thankfully.
But something has really been bothering me. BF did not say he was sorry to me. Did not acknowledge his part in this accident. He blamed the driver for going to fast. He blamed the dog. He blamed the door.
I'm not angry with my BF. I understand it was an accident, not something he maliciously did. I am mostly upset with myself. I should have boundary trained the dog not to go out the front door. When I was single it was OK, because I always put the dog in a sit stay when going in and out the door so there was no bolting, but BF isn't really good at controlling the dog or giving him commands so I should have done more to prevent this. But still. With all the times I have told BF to be mindful of the dog when going in or out, or that I routinely crate the dog when we have lots of stuff going in and out the front door, I feel like I should have gotten a sincere apology from my BF for leaving the door open.
TL;DR - Boyfriend left front door open, my dog ran out and got hit by a car. Boyfriend never apologized for leaving the door open.
EDIT: Since a few people asked, we have been together a year and a half. He moved in with me 2 months ago.
He's always had a good relationship with the dog. He pets him and cuddles with him a lot.
More details of what happened: BF came into the house, dropped some stuff off, went back out side and knowingly left the door ajar. Either the door was "off balance" and opened all the way by itself or the dog nudged it open. That's how the dog got out. Apparently the dog stopped to pee then darted into the road. Atleast that is what my BF said.


Source.

Some days are like that.