"The leaves are falling, falling as if from far up, as if orchards are dying high in space. Each leaf falls as if it were motioning 'no.' And tonight the heavy earth is falling away from all the other stars in the loneliness. And yet there is Someone, whose hands,infinitely calm, hold up all the falling." Rainer Maria Rilke
As a response to 7, 10 was holding it in so he could see all his companions again as himself and could do no longer when he reached the TARDIS. The build up of energy made it explode out of him whereas with 9 he just let it happen.