He'd managed it thus far, but as the Barkeep came around to 'deep-seated rage issues' Sephiroth's urge to fold his arms up over his chest won out. At the same time, the taller man tilted his head down towards the shorter one so that his partly raised eyebrow could clearly be seen. His expression read clearly; 'Really? We're gonna visit this?'

As the tirade went on, easily leading into events that Tifa had explained; about Nibelheim in particular, Sephiroth drew a deep breath in, raised his head away and blew a short puff of air out of his nose away from the both of them. It wasn't a comfortable conversation to be having in the street, at all.

"Firstly. Allow me to put some perspective to you that you must have missed that first time we spoke; said radioactive life-force you refer...I wouldn't be here if it hadn't been for those experiments. Moral or immoral as they might be."

It was clear it was taking Sephiroth a lot of effort in organizing his thoughts, and trying to communicate his outrage as calmly -and as a result, stiffly- as possible to Mordecai.

"As for your concerns. I don't have an answer. I've no way of knowing the exact trigger, aside from the fact that it may well have already been primed years ago...even with my very conception. But I do know one thing-"

Try as he might, there is no blunting what could easily be taken as a threat if the Barkeep weren't to back down a few pegs.

"-you wouldn't be standing here, still, if I were to flip like you say."