Is Poirot more dumb than usual? SPOILERS

My favorite Poirot moment was when the cousin was shown having his own gun, and Poirot was asked why he would risk going back for another gun instead of using his own to commit murder.

- He would not, Poirot says.

Because a murderer always uses his own weapon instead of trying to get himself an alibi and blame the crime on someone else, right?

In this movie, there are three murders.

The first murder is made with someone else's weapon, in a plot to make it more difficult to figure out and to point the blame in a different direction.

The second murder is made with someone else's weapon, to make it more difficult to figure out who did it and to point the blame in a different direction.

The third murder is made with someone else's weapon, to make it more difficult to figure out who did it and to point the blame in a different direction.

I'm sorry, but in the movie this seemed so stupid. I don't know what Poirot was doing in this film actually.