Texas - I witnessed my roommate purchase drugs. What are my legal risks/obligations?

I am in Texas.

The other day, and completely by accident, I witnessed what I believe to be a drug deal. I believe I saw my roommate purchasing cocaine (there was some kind of exchange, and my roomie very clearly took possession of a little bag full of white powder).

I have no desire to get my roommate in trouble, but I am concerned about my legal risks and obligations in this case. I have never discovered any drugs in the common areas of the house, but I do technically have access to a bedroom where the drugs might be kept. Given this and some other concerning factors, I do believe I need to move out as soon as I am able. But do I have any other obligations?

Thanks in advance.