Via collecting a SMG and receiving Two or More SMG Grenades prior to the Finale, you can use them to launch yourself over the barrier. If the strategy was used in a speedrun, it could save about 5-8 Seconds, but it would be risky to pull off, as you would need to sacrifice some health.

The SMG can be found during the Zombie Section. A box of SMG Grenades can be found on the next map, in the same room where you lose your Flashlight.