Sorry this is going to be a longer one...

So our group has a system where we rotate rpg system. We 6ish sessions in one system and we move on the next one. So after watching the Cyberpunk anime we all wanted to play Cyberpunk Red so we put in the pool for next system. I volunteered to be the GM in this, cause i am the only one who wants to be a Gm and currently doesn't have a running campaign with this group. And everybody accepted.

So yeah the horror GM will be me this time around...

But before i start to describe one of my biggest oopsies as a GM let me introduce the main cast:
-Lawman, he has a dog that is his only friend
-Tech, he made the grenade
-Netrunner
-Medtech
-Nomad, he has a nephew and and evil brother (basically Dante from DMC, i'm gonna call the evil brother Vergil)

So our ragtag band of heroes get a video from Vergil saying that he kidnapped Lawman's dog and Nomad's nephew and will kill them if they do not come to him immediately. So my favourite band of edgerunners drive over as fast as they can. In front of them they see a small 2 story high building with a thick metal platform connecting to the highest floor with stair leading to the roof. From the building you could go to the platform from a huge glass window.

Let me tell you paint you what i was planning: Our group of punks go in, and find two empty rooms with some blood stains (Vergil cut his son's arm, i was too heavily leaning to the whole DMC theme), the Netrunner connects to the entry point and starts hacking.
First floor the would have find two rooms with enemies inside, but the Netrunner could've activate some toxic gas, which would've stopped after filling in one of the rooms.
They go up meet Vergil who was sitting in front of the glass door with the two hostages next to him, fight or talk and Vergil tries to flee and half HP. In there room there was a data pad that tells you where to go next and some medicine to heal them fully.

So that was my plan. It failed.
I also made note of every material and their HP so i can calculate how much they have to damage it for it to break AND i have drawn up to the board (we use a board as a map)

Okay, after that long prologue let me tell you what happened. Our unlikely saviours arrived to the place, cleverly note that the platform is probably Vergil's escape route, so Nomad immediately yeets the grenade to the platform. And he rolls good so he hits it. So roll damage, and 35. That is impressive but unfortunately thick steel has an hp of 50, but i don't wanna be rude so i'll just make it unstable, so if Vergil wants to escape, he has to throw

And this is when it dawned on me. Both Vergil and the hostages were right next to the explosion. While the armoured Vergil with beefy stats is sure to survive the hostages with 20 (Nomad's nephew) and 10 (Lawman's god) hp might not be so lucky. Before i say the judgement let men check the hp of thin bulletproof glass! 15. So they killed the hostages, without knowing. And brought down Vergil to half hp.

Out unsuspecting party goes in, tries to recon the ground floor, when they hear the engine sound of an AV (flying car). Vergil started their escape. They bolt to the top floor, absolutely running fast the goons, which is okay, i am not evil the goons will not attack them until provoked, Vergil's bodyguards are still on the 3rd floor, so they have a fight ahead of them.

When they arrive they see the damage they caused, the dead dog and the dead boy, the DATAPAD next to the carnage and the medicine in a cabinet. And two confused bodyguard. So fight starts. Netrunner starts Netrunning. Nomad start mourning and bring his nephew to the roof and has a beautiful little funeral there. So it is basically 2v3 in a fight i planned to be 2v5, but i am not worried, the bodyguards their weak weapons, and i roll horribly. One body guard down. Netrunner struggling with awful roll not reaching to the toxic gas activator so far.

And this is when it goes even souther. Tech decides to go to the ground floor to watch out to reinforcements, and Lawman leaving to the 1st floor to check out the rooms. The second fight starts. Everybody is struggling. That is okay, Netrunner is nearing the toxic gas activation. Nomad came down after the funeral and helps Medtech who was near death. Netrunner activates the toxic gas and gets some lore (but not the next destination). The gas fills up the room and stops after that. After that they kill the few remaining stranglers what should they do? Grab the things i personally made to go highlight (data pad, thing in the cabinet) or absolutely run, saying the gas will the building.

I was absolutely clueless how to continue after that, fortunately Nomad (a veteran GM gave me some tips, how to fix this without redconing the session)

So what is the moral of the story? I don't know, i guess GMs try not to stick too much to you plan, all i had to do was to move Vergil's desk a few meters and all this mess would've been avoided, or just tell your players sometimes no if you don't what to change plans. Or explain things clearly so you and your players are on the same page.

I know this isn't exactly your scary-horror stoy you might be used to, it is more harmless but i hope you had a little fun reading this, cause the group and I are still laughing our ass off because of this session