Irrelevant. You can bet the pit was the instigator. And the truly aggressive one. It definitely has the more serious bite.
As the owner of dogs it’s been my observation that when alone they are pets when together they’re a pack. I sometimes have to let them know that death has a 0% recidivism rate.
The range of sensory triggers in a dog are unimaginable to humans. Senses of smell, sound, taste, and even adrenaline can be sensed. It’s a constant job for that dog to “stand down” on 99.99% of those trigger urges. That’s not an easy job.