This was a topic when CT came out.

Some centers fought it in the center and others did the typical pull it to the edge of the arena like you do with most dungeon encounters and many of the Primals.

Does it matter? No.

Are people inflexible? Yes.

Ragnarok did it on the North point last time I was there - Sargatanas fought it in the center - Excalibur seems to do either or.

/shrug