It doesn 't make sense.

Tsumiki exorcised a cursed spirit?

' Perplexing, and thoroughly baffling. It 's impossible to exorcise a cursed spirit without using cursed energy to do so, either through usage of one 's cursed technique or by wielding cursed tools properly. Tsumiki possesses neither a cursed technique, nor does she have any proficiency utilizing cursed tools. She isn 't trained in combat, not like Megumi and Shiki who 've been consistently receiving such lessons from childhood.

So it 's surprising, when Kiyohira-sensei tells her that

Tsumiki was the one who exorcised the curse.

Shiki doesn 't say this to be demeaning or dismissive of the other girl; Tsumiki is a dear friend regardless of any perceived shortcomings in this respect. Besides, for someone who is not a sorcerer, lack of combat skill isn 't even a 'shortcoming ' in the first place.

' However, in this case it bears repeating that

Tsumiki is not a sorcerer.