First of all, that's not how you use a katana. If you have the window to use the pommel (katana doesn't have a pommel in the first place), you'd have the window to kick or elbow the opponent. Basically, if it ever comes an opportunity to beat someone with the butt of the katana's handle, you'd have the opportunity of using your legs or your elbow first 100% of the time. You can use the butt end of the handle to injure a person's face, but it's only to the level of a bruise and does not have the power to send them flying.
If you are writing a story or learning kendo, don't copy this scene. It's only fantasy. You don't sword like that.