To dream of an army tank represents decision-making that is defensively expressing power. You or someone else that is stubbornly forcing certain choices or actions. Feelings about yourself or someone else that is very serious about enforcing their views. Having no fear about totally disrespecting someone to make them do what you want. "Rolling over" your competition to permanently destroy them. No fear of "crushing" people to enforce your decisions. Feelings about decision-making needing to be totally insensitive in order to win an argument or struggle. No concern for what anyone else thinks or feels if they are in your way. Heavy-handed enforcement that refuses to listen.
Negatively, dreaming about a army tank may reflect an excessive bossy attitude. Dishonestly overpowering people by whatever means are necessary. Crushing opposition you don't want to listen to. Humiliating people with less power than you because you don't want to reduce your own power. Excessive enforcement.