He should've heard something, but it's late, and his head is pounding, and it's taking all his attention to focus on the tinny voice of his text reader. And so when the giant arms sweep him out of his chair and cradle him to a broad chest, he's unprepared.
His dagger is in his hand just a second too late, pressed against the intruder's throat, but by then the recognition hits him.
"Gladio," Ignis says, "put me down."
Laughter rumbles in Gladio's chest, reverberating in Ignis' bones. "No can do. Noct sent me to tell you that none of us is young anymore, and you're not allowed to work through the nights. You're going straight to bed and I'm to take you there."
"You're really testing my unwillingness to stab you right now."
"Promises, promises," Gladio says; the leather of his coat is pleasingly cool under the scars on Ignis' right cheek.
Old man at forty or no, Ignis can twist out of Gladio's grip; but the King's orders are the King's orders, even if they're ridiculous, and Ignis' work can't wait on this nonsense - and Gladio's arms are steady and warm, holding Ignis securely amidst the familiar darkness.
Nobody else could ever make him feel so - small; safe; held. He slips the dagger back into its wrist sheath, and lets himself relax into Gladio's arms, and prepares to enjoy his surrender.
"Well, then," he says, "I hope you're not decrepit enough to drop me before we reach that bed."
Gladio laughs again, presses a fond kiss into Ignis' hair.
"When had I ever dropped you, Iggy?"
It's three hundred steps from Ignis' office to their rooms at the Citadel - Ignis knows the number by heart, walks it blindly every day - and he's soundly asleep by the hundred and one.