Last Survivor vs 19 Zombies in Attack of the Undead 20 - CODM

It is almost impossible to win as the last survivor in Attack of the Undead 20 because there are twice as many zombies. It is especially harder on the Meltdown map, where there is no safe camping spot with a ladder that has only one entrance. It is just me holding off 19 zombies for 4.5 mins and getting 68 kills.

My strategy:
Use baseball bat to kill when they are too close to shoot.
Place sentry gun and keep running in that direction with zombies following.
Have zombies follow through a narrow opening to shoot them easier.
Hide to launch the nuke.

Game: Call of Duty Mobile

Call of Duty Mobile username: GeneralAmiri

Game Mode: Attack of the Undead 20

Legendary Gun: PDW-57 Toxic Waste