Dazai and Atsushi swap minds when they bonk heads. Datsushi doesn’t mind, but Azai wants him to stay out of trouble. Atsushi tries to get back at Dazai for all the times he’d surprised him.
What would shock Dazai-san is you 
not being surprised by what he does.
الشّيء الّذي قد يصدم دازاي-سان هو 
.عدم تفاجئك بما يفعله دازاي-سان
Du darfst dich nicht davon
überraschen lassen, was Dazai tut.
Tan solo deja de sorprenderte
por lo que hace Dazai.
C’est que tu ne sois pas
surpris par Dazai.
Ciò che scioccherebbe Dazai-san è vedere te
che non ti sorprendi per le cose che fa.
O que deve fazer é não se
surpreender com o que o Dazai fizer.
Всё очень просто!
Тебе надо не удивляться действиям Дадзая.