This one sounds like a complete pain to pull off and it would be if you do it normally. Thankfully, there's an easy solution detailed by the folks over at XboxAchievements (all credit goes to them obviously). It goes as follows:
The best and easiest method is this: load horde map 'Not So Pleasantville'
. The first wave should be 'KILL THE ZOMBIES! (35 of them)'
. Run northeast towards a red explosive car near 2 cop cars & you'll notice 2 barrel drums. Climb on top of the one that is standing up, wait here for 88 minutes. Here is a screenshot on what it should look like: https://imgur.com/qAwprJR
I recommend that you time yourself and leave your controller plugged in (charging or use a wired one) so that it doesn't accidentally turn off. Remember that pausing the game stops the timer. Occasionally move the
in any direction just to be safe. Once you reach 88 mins, let the horde kill you. The achievement will pop.
There are a couple of extra things I'll personally add (thanks to those in the comments). First is that you need to stay on the first wave as going beyond that will spawn acid spitters, which can and will kill you while you're on the barrels. Second is that this achievement is glitchy, so it may not unlock even if you do it all correctly.