INFO:

Ok so I have 3 theories (I think it kind of mixes into one) 1.Dazai would volunteer to go back to protect to the other agency members from what he experienced there (all the bloodshed and what Mori used to do to him- not physical)- especially if atsushi got selected. I believe he’d volunteer to go back if anyone got selected but try harder for atsushi. 2. We know that the president said that yosano and ranpo under no circumstances are allowed to be selected, nothing is mentioned about dazai not allowed to be selected. That could link dazai could get selected. 3. Moris predictions are never wrong and he predicted Dazai would take his place when Dazai is 23, and he is 22 right now (in the anime) and we all know Mori wants Dazai back, despite his fear of him.