Have been following this discussion from the beginning.
Asha, I agree with your reasoning completely !
Nithya, please be clear about whether the said person wants to 'grow' or whether he wants to 'take over' from you!
Theres a difference between the 2 - if he is ambituous and has leadership qualities and wants to move on to the next level - lovely- if hes managed to do it in 10 days of oppurtunity - he's a real acheiver!!!
Now the next angle, if he is trying to 'take over' from you specifically, and wants to see you out and 'not' obeying your orders, then theres a personal grudge and its actually a matter of work place conflict. Please differentiate between 'not obeying orders' and 'doing more than ordered' (which means hes taking more initiatives than others).
If hes not obeying, you can simply act like a boss- give him a couple of warnings and take his case during appraisals. Why worry?
I really would suggest that you become freindly with him and discuss with each of your team members about their individual career graphs.
~Shikha