Ok, sure. But I did explain earlier, why things occurred in the order they occurred in, is simply a means to facilitate solid boss fight mechanics. A boss is a test of the player's skill, specifically, certain skills the game wants to test you on at this stage in the game. This is something you have to consider when providing alternative suggestions.
Royce suddenly running away to rig the building to blow doesn't fit thematically because he was never established as a demolitions expert, and why he would do such a thing doesn't make sense strategically because he has a small army to take you out, as well as an armored exo-skeleton to gear up to should you actually succeed. He also strikes me as a character that would very much enjoy taking you on toe to toe, rather than outwitting you as a tactician. Rest assured though, as I'm sure there will be characters we face off with in this game that can give you the interactions you want, it just isn't Royce.
Also, I like the suggestion that we can let him live if we choose to, but to have this option after we've chosen to attempt to kill him in combat is rather redundant as the game already provides the option to not kill him, which would be the non-lethal option(s). Furthermore, it wouldn't make sense for a character like Royce to either beg for mercy or simply accept defeat, i.e. if you give him an opening I believe he
will shoot you in the back (that may be a cool outcome, actually).
I apologise for dissecting the minutiae of your argument, but I'm just really analytical by nature and I feel if I break things down in detail you'd better understand where it is exactly I'm disagreeing with you and why. Maybe even change your mind on certain things.