Guessing it’s probably #2 wylk- it’d be unthinkable to even consider a removable central style on a vault of that caliber.
Yes, the use of smaller emergency doors seems to have diminished in recent years, but where they have got the sense to incorporate one, it makes far more sense to make the second door full size so it can be used as normal by staff and customers, and not like the old days where using one meant a 6 month diet to slim down and crawl through it.
Both doors are side by side leading to the same immediate area, so the doors could be used on an alternated system of days or weeks keeping both in working order and either one acting as the emergency.
Regarding the rectangular bolts, quite a few european manufacturers have been using them for some time now- notably German makers spring to mind.
I’m guessing again here but think this is probably the reason- rectangular bolts can be cut far more cost effectively from heavy steel plate or sheet by the same automated machines (CNC Laser, water-jet, plasma etc) that are being used for cutting of the door and body anyway. Overall it saves time and costs as it eliminates round stock being turned on CNC lathes, drilling, tapping threads, additional welding etc. I think it’s all that competitive out there these days that they have to save and slash wherever they can and we’ll probably see more such changes in the future.
The days of properly ‘engineered’ safes with turned bronze bushings and precision fits are long gone- running fits from laser cut parts are as good as they seem to get these days!