No swords seen when we cut back to Xebec, that gesture also looks weird or quirky.
@Reborn already said it, normally that’s not how you use your fingers in a conversation or for example if you’re holding up a number. You hold it up to your face in a conversation, his fingers are at a relaxed/lower angle here.
Ya it's not related to question.
Xebec is the one who cut the mountain with his fingers. He's not carrying any sword as well so not a swordsman (a swordsman always carry his sword and we can clearly see WB blade and Shiki swords) ...
Normally, when we ask questions then we raise our fingers right to the level of our face and then use fingers to signal numbers of questions
Fingers either face the person we are asking questions or towards us....we all do it in same way....in short fingers stay parallel to the person
But xebec fingers are parallel to the sky or ground......
Law use it in his room....
So, either he used Ope ope no mi...
Or
Some advanced haki....to cut mountain