Escapes are the defensive side of positional BJJ. Every dominant position has established escape sequences: mount has the bridge-and-roll and the elbow-knee escape; side control has the hip escape to guard recovery and the roll to turtle; back control has hip escape and shoulder drop.
Good escapes require frames to create space, movement to exploit that space, and timing to act before the top player can tighten up. Beginners often try to escape with pure strength; intermediate practitioners learn to make space first, then move into it.
Defending submissions is also an escape context. Tappping is an escape, but recognizing danger early and adjusting position — tucking the chin, hiding an arm — prevents submissions from completing. The best escape is not needing one.