10 ft is absolutely negligible distance in terms of the earths surface and being off of perpendicularity to rotation.
Did you notice that in the beginning of the video, they waited for over a minute before pulling the plug, to make sure the water was absolutely still, but after moving supposedly off equator they pulled the plug almost immediately after filling the basin?
I did notice that they waited on the first one, but not on the other two.
I may rewatch to see if the direction of pour set up an incipient rotation (i.e., did she pour on opposite sides of the plug to help initiate a swirly).