@unime: I'm on the opinion that Aquila just suck at choosing his words/showing proper expressions.
Like, his last line might actually be that he really hate how Uri get pulled so EASILY into a trap like this because it makes it really hard to protect him.
So this is working on the assumption that the girl who stabbed Uri is also the one who 'coincidentally' talked about the witch in the castle right when the two walked by.
Well, what if that wasn't a coincidence?
The idea is for them to rile up Aquila to get Uri to interfere and break them apart, then kill Uri because that'll make Aquila sad.
That might've even actually been what happened in the past.
So when Aquila saw that girl, he KNEW she's the one who lured Uri into a trap.
So when Uri interfered, what Aquila really meant was "are you choosing to die (i.e. getting lured into the trap) to protect this girl (that will lure him into said trap)?"
It'd also be how Lamia who's so insistent on making Uri the Duke would become Duchess, if Uri is dead he can't inherit the position.
So the maiming of Uri's hand (and avoiding healing it) in this loop would mainly be to make it clear to 'everyone' that Uri isn't on his side, and thus no longer a target of assassination.
At least this is one possibility that I can think of that would make sense and be consistent with his current "I just wanna protect you" puppydog mode to Lamia.