I'm not 100% sure if the one I replaced a few years ago is identical to yours, but the bulkhead I have left over from the replacement I did looks like the best way to remove it from the flat car is to gently apply pressure to the 2 smaller tabs on the edge that aligns with the end (short edge) of the car.
The entire bulkhead piece can then be moved to free the larger tab along the length of the car from the slot.
Fully agree that if you tried to apply any pressure to the single tab on the part of the bulkhead that is on the long side of the car that it would break long before you were able to get it through the slot.
-Dave