He had zero choice.
I agree he was in a bad position but the reason he has such fanatical followers that have no clue what he stands for or just plain do not care when he comes out with a democrat position is because he stood up to every single attack and gave it right back to them. He came across as the bullied brave person standing up and fighting the MSM and the GOPe. Instead in the last week he came across as a child instead of their hero of the moment and he lost his momentum where he did not have to give any real positions.
He has come out with more jaw dropping position comments in the last few day that are flat out scary if you are a real Republican picking someone to vote for now that we are not focusing on his comebacks and that has been horrible for him.
He was a cult of personality not a candidate standing on positions. He let that popular part stand down.
Carson might not endorse Cruz if this is true:
http://www.msnbc.com/msnbc/carson-other-campaigns-sabotaged-us-dirty-tricks