If Chronomantic Escape is in your hand, cast it by paying 4.
Otherwise, activate The Tenth Doctor by paying 7, causing you to time travel three times, removing all time counters from Chronomantic Escape and cast Chronomantic Escape from exile without paying its mana cost.
Resolve Chronomantic Escape, preventing creatures from attacking you until your next turn, and exiling Chronomantic Espace with three time counters on it.