Just make the time to get back in longer than 5 seconds. I was once running around, a battlefield popped right on top of me, by the time I realized what was going on, I was out of the tiny area and 5 seconds were up. Great. I once ran to what I thought was the edge to rest. Turns out I was just outside the zone - 5 seconds doesn't even give you time to get up from a crouch to get back in.

Knockback isn't the problem - 5 seconds to get back in is.