Stuck in Warhammer 40k(isekai)

This is a dream right?

POV ???

First thing I have is a very nasty headache. Where am I??? I notice i am in a pitch black room and i am standing up, i look down but do not see my body but armour, looking like terminator armour. How much deathwing did I play last night? Well I am having one of those dreams again. I am a terminator but i notice my armour is not bone white, but blue, hydra blue. Am I an alpha legionary? Well I try to move and I move like a terminator, but I need to watch my step and it is harder to move and it feels too real. Maybe when I wake up I will have more details of this dream. I feel like I am a walking tank and it is quite heavier, it feels extremely real and I keep walking. I finally noticed my surroundings. I am stuck inside a large corridor and noticed it is massive, made out of concrete and there are rails on it. Some type of metro? I finally noticed I was holding something in my hands and looked, one very ornate power axe with gold around it in one hand and one volkite charger in the other. I am a Lernaean terminator of the alpha legion. I continue to walk in the darkness and see my surroundings without trouble, most likely the Occulobe organ doing its job. I should be scared by the darkness but I am not. It seems I do not feel fear and this confused me beyond doubt. Every dream I had I was scared shitless. The more I walked I noticed there was damage, battle damage, with some parts of the areas collapsing in and shot marks, most likely lasguns, wait how do I know that? I continued my march and the state of my armour became apparent. It was damaged, as if it was struck by some type of fire, but Cataphractii Pattern terminator armour did its job.

I kept walking to what I feel were hours. I found some light at the end of the tunnel and walked out. The rails continued on a bridge but there was a mighty chasm, but it was man- made. I was inside a hive city and this was a divide there with many other bridges interconnecting both sides and the chasm was massive. Perhaps a way to divide districts? I noticed a heavy duty elevator to the side leading upwards and so I took it to see what else this place has. As I go upwards there are more signs of battle with rubble and other such damages such as blood, but not bodies and this puts me on edge. Perhaps the genestealers are here? I slowly walk forward with charger in hand ready to blast anything that charges at me and then I hear something and the Lyman's ear picks it up, a cry for help coming westwards from a door leading to multiple corridors and I march ready for close combat and possibly genestealers. The cries get louder as I slowly close in and there are more corridors and doors, this possibly was a habitation area for civilians. I see a cave in the corridor and it seems it is where the cries are coming from. As soon my footsteps were heard whoever was saying stopped and there was comotion from the other side of the wall.

"WHO IS BEHIND THE WALL GET READY FOR I AM GOING TO TEAR IT DOWN" i say with a surprise to how loud and deep my voice became. And with a hit of my axe I broke down the wall to reveal many trapped guardsmen, with cadian style equipment. They are all ready to shoot but when they realise i am an astartes they don't. They do not know I am one the alpha legion. One of them approche me, a sergeant with a chainsword in hand. He give a small bow before asking

"Lord astartes how can we be of service" his voice with an odd accent.

"How did you come to this situation?" I say with curiosity.

"We have been overwhelmed by the genestealers, we were preparing for rear guard action, but the ground gave in and we ended up here" He points to the other side with crumble stone and a genestealer arm getting crushed with only its hand outside.

"Gather your men sergeant, we must get back to friendly lines and figure out what is the current situation, Genestelaer have the advantage down in here thus we must go to upper levels where they have less spots to hide" I bluntly say and the guardsmen follow my lead, their is in total 12 of them, i do not buy the rear guard actions story, they must have fled, but extra firepower is welcomed. We continue the march onwards to go back on my previous stops, seeing more signs of the devastation of the conflict with more of the infractruce damaged and many areas of the once thriving hive city torn asunder. It was a hard time walking in such places as a terminator, but I could walk through them. Soon the night began to settle and we needed to find cover, and we found an old chapel to spend the night and barricade ourselves in it. The guardsmen of this world were trained in the cadian pattern by the looks of their armour and by how they barriaced this area they are no pdf.