Yes we do need Mental Prayer for Salvation: So let St Ignatius Loyola show us where to begin.

Meditation & Mental Prayer: Catholics Talking To God.

St Ignatius Loyola wants to show us how to become perfect through Meditation and Mental Prayer. So he begins at the beginning, that is with God and our relationship to Him. St Ignatius wants us to understand the reality of the grievousness of our sins which are a huge insult to God.
In helping us to understand the magnitude of our offenses, Ignatius shows us the Majesty of the Most High God who as Our Lady described at Fatima, is “…already too much offended.”
To enter into the depth of God in prayer it is necessary to remove the barriers that block our way. Those barriers are our sins and our faults. There is no way around them. They must be removed first.