No other choice indeed, and while he likely would have gone through with it without question... There is a reason he swore more using Shiva's name or the stars in general instead of Bahamut's. Unless it was to curse.

Because he will do anything, anything to save his people; their Star. And it tears him apart inside knowing what's likely happening without him there and the Oracle line being snuffed out completely. How they're likely suffering an eternal night with little hope of day ever returning. He tries not to think about it, but at night... it all comes back.

Why does he get to enjoy the sunlight when his people suffer in the dark?

Yet like with many things, he keeps his mouth shut. Only continues to hold onto Ignis and the reminder that he isn't alone. That something other than him is solid. He's silent for quite some time save the shaky breaths that don't quite become a sob, yet as he starts to calm...

"...Ardyn's boot is the last thing you remember, right?"