I have a 05 civic ex last week I was driving home and the car died on me on like a mile trip up the road. Got out the car smelt like eggs . I though maybe the cat was plugged. Car cranks and dies within a second .got it towed home. I did a fuel test and its getting spark. I looked inside the oil cap while the car is being started and the rocker arms are moving. I don't think the timing belt broke but maybe just slipped a thooth ??? Just like in this video right here . It's doing the exact samething

https://youtu.be/i6x31RU1S_I

No codes are being shown at all
Exhaust isn't plugged I disconnected the manifold to the cat still does

Any suggestions ??

If the timing is off by just a tooth or two will the motor be ok ?