I agree tecnamflyer, unless you feel the result might be catastrophic otherwhise, why add more confusion in an already stressful situation? Clearly and unambiguously complete the handover of control and take it from there. It won't be the last time in your career that the handover will be interrupted, I would try to keep things as simple and as unambiguous as possible.
It might be more interesting for yourself to analyse why there was a trigger to take matters back in your hands. If you were not in an acute life or death situation, then why react that way? If you think you were more in the loop of where the plane was going, then why not use that superior situational awareness in a monitoring roll?
Having said that, handover back and forth of control is often an issue in stressful situations, been there, done that. It takes strict discipline to avoid confusion.