[Whewt22]

Just found this, kinda supports some of my previous posts so i'll share it with you guys!

"So anyway, I'd bet the hollowization of everybody has something to do with the area and the strength of the soul. Hyori got her ass handed to her before Shinji arrived and then began coughing her mask out in -101. So her soul had been weakened enough for the hollowization to begin. However, she still had enough strength to get mask first (remember back to Ichigo & the hole).

I think Aizen & Co. used the same sort of hollowization method earlier on with weaker souls and they 'sploded because they hadn't the strength to resist hollowization (souls dematerialize and rematerialize before forming their mask and becoming a full hollow). As one of the observers of the experiment says "I see, so an ordinary soul can't handle it properly". Hyori, Kensei, and Mashiro however could handle it, being stronger, so they got mask first and started battling to control their hollow.

Before Kensei and Mashiro hollowized Tousen weakened them, before Ichigo hollowized Shinji knocked him out, before Hyori hollowized Kensei beat her ass. So hollowization requires two things: a strong, weakened soul and some random thing Aizen will explain to us in due time. (Oh, and Ichigo tired himself out trying to get out of the hole before his first hollowizing but that situation might be different because it delt with a plus soul, not a shinigami soul."

-Some random person