Need to know how to make a wall disappear after 100 seconds. Details: Tier slayer gametype, 1v1x8 or 2v2x16
If you want exactly 100s you need to use a speedpile gametype and have an object spawn that scores the object you want removed. That however makes setting up coherent scoring for the game difficult. You can gate a wall in invasion and have it disappear with a specific tier though. Then you could set the time limit for the tier to 100s, but if the players captured the objective sooner it would happen sooner. If you made the objectives inaccessible you wouldn't have a scoring system, but you would have timed tiers for manipulating your structure.
^This. But it wouldn't work for anything competitive/slayer-related, so you can consider this a solution in case of need.