The obligatory precaution is to move the body part being washed (next) out of the water and then re-entering so that the intention of ghusl precedes the commencement of washing. However, some splashes from the tile are not significant, it is that you make the intention and then start washing (rather than being under a continuous flow of water during the intention). As such, just move your entire body out of the stream of water, then immerse your head/neck and continue to your right and left sides.