So, atm when you take control of a friendly bot in local play after you died, it basically ends the game. You manage to take control over the bot, and a few seconds later you simply cease to exist. You're back at the respawn screen, and when the countdown to the next respawn wave comes to 0, a wave is wasted and the countdown sets to 9secs again. It keeps doing that until you run out of waves and eventually lose the game.
Thanks for reading !