For my story, the leader of a group of villains, has leverage on all the other members of his gang, in case any try to turn on him.

Basically the main character, a cop, manipulates the leader into going to get leverage on one of his members, because then that will lead the MC to where the leader is keeping the leverage on everyone, and the MC can use this expose them all then.

I wrote it so that the the leader goes out to the middle oh nowhere, where all the leverage on everyone is buried in the ground and the villain digs it up. The MC follows and waits for him to dig it up.

However, I was told by a couple of people that I asked that they felt it was a plot hole, cause why didn't the leader just keep it in a safety deposit box or something like that?

Does this count as a plot hole?