The sound of the wall breaking is what made him turn around, but we then see a hole in the wall (to the point where the light from outside can be seen, which means it is pouring into the room), it then shows a close up of his eye looking shocked (showing that he is reacting to the light from outside) that is shaded which shows us the light from the wall hasn't reached him yet, and then it shows him speed out of the way before we see Rukia illuminated in light, and then finally, it shows him in a shaded part of the room that isn't burned at all, showing us he wasn't touched by the sunlight - as being touched by sunlight is what reveals his true form, the anime contradicting this doesn't matter - the manga is the primary source material and doesn't show this.
It's like the most blatant speed feat in the series, and it so painfully obvious to anyone who has any understanding of paneling whatsoever. Anyone who disagrees with this feat doesn't know how manga paneling works (Which would be the wall, then the close up of his eye, then the panel of him outrunning the light, then the panel of him phasing back into existence, then the panel of Rukia saying 'What?', and finally the panel of Rukia saying "Why is he running?') and any thought other just doesn't make sense.