[Citadel Boss] How do I dodge this?

As title, I am dumbfounded against this phase that lazer repeatedly cover the whole arena and slow me down to a slug while also damaging me with no apparent way to avoid.
Please enlighten me.

Not sure as haven't got that far, it looks similar to the old t17 Citadel map, which was based on expedition boss Uhtred arena.

There is a video of it on the wiki. https://www.poewiki.net/wiki/Citadel_Map

Looks like the spacing on the arena you are doing is less. If it is the same effect, there may be information about it on PoeDB or someones t17 guide that might be somewhat relevant. I don't know anything about the damage type or any debuff that it may apply. I know there was slow debuffs in the old version. I thought they came from other skills and not the lazers themselves, but I'm not certain.

Mostly when I was doing t17 maps, I was doing it characters that we're not affected by slows, eg jugg/trickster, because the slows made them very tough without high dps. Unsure of the current state, and what the mod interactions are at the moment. If you're in trade league there might be some tech you can swap in for the fight on other classes. Eg. balance of terror while casting temp chains. I think it is an action speed related debuff, but uncertain about that as well, you would need to look it up to see if that would work. It might be a regular slow on movement speed.

Seems like I probably wont be handling that content on my current HC character that has no defense against that sort of thing.

Thanks for the info.

This is indeed the old T17 boss in the new "Nightmare Map" format. In the old version the lazer always have a gap (about 4 lazers wide) which will not fired, create a safe space to stand on in all 3 ways of fire (diagonally to the left, diagonally to the right and straight down).
However in this version those gaps do not present, making the only safe space for diagonal lazers to be the opposite corners and the straight lazer to be unavoidable.

I am not sure if this boss received a rework and require some condition to either activate the gaps or disable the lazer or if it is something else entirely so I posted it here seeking info from people who went further ahead of me in the league.

Yeah I can see what you mean. Hopefully someone who has completed can provide a bit more information.

[Bump]
Er... Does anybody have an idea on this?
Since this thread got a fair bit of view yet no one seem to have a concrete answer, I start to think this might be a bug.
@GGG could we please have an official confirmation if this behavior is intended? So I can at least try to science it out myself instead of having my atlas point hanging in wait like this.

It used to have some gaps in T17 maps. But now since the nerfed t17 aka nightmare maps by removing a lot of mods that had to do with "slow" I think they buffed the beams to cover all map. There a somewhat kind of a solution but it doesnt really work since the beams fire very rapidly without any pause duration. There are some gaps your character can find to the sides. That way you can avoid the beams if they are shot verticaly. But that's is not a real solution since the boss arena is huge and the sides are far away and by the time you get there you are hit, by the time you get back to the middle to fight the boss, the next beams will hit you also, if you are a melee build like I. I just endure anything, I can outank it , even if I hit the boss once every 5 seconds.

Tested btw.

To whom this may concern:

"

Fixed a bug introduced in 3.28, where the array of beams from the mirror in the Nightmare of Uhtred fight no longer had a medium-sized gap in the middle of the array.

I guess it is indeed a bug, and has been fixed in the latest patch.