There's a considering silence at Byleth's question. Though he does not doubt he would be able to similarly throw those he has bound, neither can he trust that they will meet their end on that alone. Likewise, while he would be easily capable of destroying the intelligence devourers he has seen first hand what can come of their destruction, and not just in this moment.

"Were this my own world, such creatures as these would be bound and consigned to Pandaemonium, there to be bound permanently." A pause, and the briefest of sighs. "Here, I do not believe the magicks of interment will find such sway. I may be able to enforce some manner of silence upon them. I cannot promise it will spare us what may come of their destruction."

But it should, at least, spare them the attention of any more and unless Byleth has any strong objections, Lahabrea sets about working the spell that will enforce at least a temporary silence on the creatures.