It can at a casual glance appear that the Oregorger area is a complete maze and his rolls are done completely at random, at least it did to me, but after a bit of a closer look I realised that it's actually a pretty straightforward pattern. Once we got our heads around that in our raid group it helped a lot towards the kill.
Partly out of a desire to help others, and admittedly partly out of boredom, I've made a diagram/map illustrating the way his rolls work for those of you perhaps initially bamboozled as I was.
This image shows a map of his area that I drew expertly in MS Paint. Immediately note that there are a total of 8 different 'crash sites', represented by the stars on the diagram. These crash sites can actually be collected into pairs to simplify it down to 4 crash sites, each made of two adjacent stars.
The reason we can do this is because at either of two adjacent stars the choice of direction Oregorger faces is the same. He either follows the blue arrow, 'going outside (or long)' as we dubbed it, or he follows the red arrow, 'going inside (or short)'. As far as we could tell, at each site he has a 50/50 chance of going either way.
To aid understanding, imagine he consistently chose to 'go short'. That would mean he would constantly follow the trail of red arrows from red star to red star clockwise around the room. Conversely, if he were to consistently 'go long', he would follow the trail of blue arrows from blue star to blue star anti-clockwise around the room.
So how does this help? Well, once you have an understanding of the pattern he can follow, it becomes a lot easier to tell at a glance whether the lane you're currently in is currently safe, and once you see which way the boss turns you can pretty quickly figure out where he's going to end up and whether or not that is going to threaten where you're currently standing.
Just a little bit of something I drew up at 3am, if it helps even one person get a kill I'll consider it worthwhile.