That's exactly what IRS hack Lois Lerner did in front of a house committee looking into the IRS targeting of conservative groups. She simultaneously exercised her 5th amendment right against self-incrimination while saying she did nothing wrong! And as some members of Congress belive, if you make ANY statement regarding your guilt or innocence, you have effectively waived that right by commenting. And remember: these IRS hacks can make your life a living hell but expect to play by different rules.
And then there's this outstanding exchange between the former head of the IRS and Rep. Trey Gowdy.