Animated Armor

I have a question, you do not have to answer if you don't want to:

If a player were to wear the armour in its dormant state, would the armour be able to take over the player's movement and sort of force them to fight or even kidnap them in some way?

It would only affect the player's movement, so spellcasters can't be forced to cast spells that require a verbal component. That and other players might not recognise their friend stuck inside.
Perhaps the only to get them out is to remove the armour in some way of dispelling the magic long enough for the player stuck inside to get out. Or if the player is strong enough, they can try to resist an action but would be very difficult to remove the armour on their own.