Revealed by a stranger, we learn of the reason behind Serizawa's anger. Later on, the Roshigumi receives a new name.
They must not balk at 
dirtying their own hands
يجب ألّا يعترضوا على تلطيخ أيديهم
No deben oponerse a ensuciarse las manos
No deben oponerse a ensuciarse las manos
Non dovranno rifiutarsi di sporcarsi le mani
Serão obrigados a sujar suas mãos
Они не должны бояться запачкать руки