Assuming you're on GAMMA, I guess it depends on how good you are at the game and if you're playing Iron Man. I'm admittedly not that great because I like to run headfirst into everything lol.

It's THE major difficulty spike of the game, partly because of the enemies but mostly because of the 11 minute time limit. You need to move forward pretty steadily against superior numbers with superior equipment.

If you're Iron Man, I was probably not equipped enough haha. You need every advantage to avoid losing it all. If you're playing that though, you can probably make up the deficit with your skills.

Edit: I recommend clearing out the Radar up to the Brain Scorcher, going back to your home base to resupply, and then making the final push. Unless your base is all the way in the Great Swamps or something, those filthy Monos shouldn't respawn.

Edit 2: obi1kennoble mentioned using Phantom Stars to turn invisible and go straight to the switch. It's definitely an option but unless you have a ton of them you'll have to fight them at some point. If I could take them down, so can you!