Why??????????

2 brown enemies, 2 Mario portals (green tubes) 1 question mark mushroom block directly above. Seems to be the last switch/room of this area. It seems to me that the only way to break the question mark block is for it to be the very first thing you do, but if it is the first thing you do, the mushroom inevitably gets broken by the top brown blob enemy. Am I missing some mechanic or something?...