Muriatic Acid Questions involving cleaning concrete…?

First, is muriatic acid safe to use indoors when diluted? I am using it to ‘etch’ my concrete walls. I am hoping to remove the efflorescence so I can use ‘Drylok’ to waterproof the walls.

It says to apply, let it sit, and then rinse it. When I rinse it off the walls, it goes onto the concrete floor. Since it is impossible to get it all off the floor, will it harm the floor?

Any other tips or information for using muriatic acid for this purpose?