You will understand that i cannot go into explanations or example code here. the descriptions that Alex has come up with are: "unencrypted TDE key in the SGA" and "unencrypted TDE key logged to trace file with special events". These issues are in my opinion high priority considering the effect of leaking a key and the new functionality being heralded. The only saving grace is that it is unlikely that there are many, if any customers live in production on 10g R2 unless there are some beta customers who are using this version.
I was also discussing with Alex my opinion that some of the usual suspects in the Oracle security world should maybe invited to participate in the beta (or even alpha) programs of new releases so that fresh eyes are applied from a security perspective to new versions and new functionality that is going to be unleashed on the public.