The reason it's not working the way you have it is because you've set the timer, but you've told it to do a gameover immediately. The timer is for setting switches and things to be modified at the expiry of the time period. If you want to have something happen at the end of that time, you need a different event, or a different page on the current event, to be conditioned by the switch that the timer is modifying. Any commands you add after the plugin command will just happen as soon as the plugin command is run.
The post above is also incorrect, as the self switch is still being turned on manually (not waiting for the timer to turn it on), causing it to go to the next page straight away and execute the gameover.
What is path1.gameover? That is meant to be a switch id. Unless you have some plugin that's going to interpret path1.gameover as a number, that argument is not going to work.
What should happen if the player goes to another map while the timer is still running? Should it still be gameover? Should it only be gameover when they return to the current map? Should the timer be cancelled if they leave the map?
Also, you've really got some serious issues with your event. It's an autorun event, with a single page, conditioned by a self switch. That page will never be run, and if it WAS ever run, it'd never end, so the timer would keep getting reset each frame and would never run out, even if you removed the gameover command. Exit Event Processing only works on player-initiated triggers, not on autorun or parallel process events. I suggest you take a look through the tutorials at the link in my signature and learn more about event triggers and event pages.
If you just want it to execute a gameover no matter where you are, when the timer runs out, put this as your command:
AddTimer gameover 60 SceneManager.goto(Scene_Gameover);
but it's still not going to work until you sort out the trigger and page conditions.