A player illegally taking their own money off the table.

Removing money, or chips, from the table, which is not allowed.

this is some kind of cheating where the player steals money from the table.

Ratholing is a word to describe a conversation or process that has has deviated from its original productive purpose into a generally unproductive but long and winding detour that eventually comes to a dead end. If you are part of such a discussion or process you can describe this as being ratholed or being in a rathole (or rat hole).