Watched the episode last night and I too though that scene odd.
Umm ok so you caught me putting cash into a safety deposit box in a bank, BFD.
I would think the real crime would be you coming into said private area without any kind of warrant or provocation to do so and one would think a lawyer would quote that straight away.
Well that's probably why the producers made this particular lawyer be so wimpy-- because they needed someone who looked like he would easily fess up to the DEA. And even Saul says the guy was a moron.
Of course that begs the question of why Mike didn't do a better job selecting someone to handle his money in the first place.