I 'm a mgr at Big 4. I just got fired by the client. I made a mistake due to time restrictions and incorrect data coming from the client team so handed over the work without a thorough check and ended up biting me in the behind. My partner seems annoyed, but I'm also annoyed the fact that I was staffed on a project completely out my skillset and because all the meetings and decisions happened behind closed doors without me being afforded an opportunity to explain. Regardless, the fact is I messed up and the situation was managed poorly by me and I take full responsibility for that. My question is, should I do hakiri ?

Once again you handed over work without a thorough check. It's Harakiri, and yes you should.But also, just roll onto another client and be more diligent? Unless you are on performance measures already this shouldn't be that big of a deal

You made a mistake. You took responsibility. The end.Leadership isnt about being right all the time, its about taking responsibility when things go wrong and keeping it in context. Move on. If people can't let it go, let them go.