It sounds to me like while a part of the issue might be the mech itself (I just call it out loud which sides are safe, keep repeating it and memorize it as well as possible before it happens), another seems to me is snapshotting.
So here's the thing,
The /moment/ an AOE marker is gone, the snapshot is taken. The area is now safe. This /feels/ wrong, but you can walk right into beams and flames and everything that looks like it'll kill you and it will /never/ hit you. The moment it feels like it's the least safe to be there, it's safe. Walk right into those tasty beams like a moth!