Quote Originally Posted by DarthEnderX View Post
1:57 on SubsPlease version. Earlier than I remembered it being.
Got it, I thought it was during the fight.

Seeing the scene I'm not sure if it has any significance or if it was something the animators chose to show randomly just to illustrate that Rimuru felt something in his "gut" to give Chloe the mask, and used Veldora for that purpose.