What is it with Murata taking exposition stuff from later and putting it into earlier chapters? Wasn't this arc intense enough already?
! I assume One intends to give Tatsumaki new flashback during the Tats and Saitama fight arc whenever the manga reaches that point. One probably figured that even though
a ton is going on right now, Tats is practically the main character right now so its best to get in some of her backstory now and is saving the meat of it for the next arc.