There is an episode widely known through novels and so on that is interpreted in many ways; according to versions of this episode, TAKECHI was anxious that a weak natured Izo may easily give into torture; or that Izo may go under a far more severe torture than his other comrades due to his frivolousness; or that Izo received the poison and drank it (not knowing that it was poison), but did not die and confessed for not being able to withstand the torture; or he confessed in anger in finding out that it was poison.
これは小説をはじめ広く知られるエピソードで、それらによればこの際、武市は性根の弱い以蔵が拷問に簡単に屈してしまうと心配したとか、以蔵が軽輩故に他の同士より一層激しく耐え難い拷問に遭うであろうと予想した、また、毒を送られた以蔵はそれを（毒とは知らずに）服んだが死なず拷問に屈して白状したとか、毒を見破って憤りのあまり自白に及んだなどと様々に解釈されている。