What stuck out to me is cops were blocking it after you went through. Can you expand on this? Did they pull up after you and the other car entered or was it like they were already there and you somehow ‘drove past the car block without noticing’?

Often times stuff happens and just doesn’t make the news, nobody calls it in to them. And sometimes stuff is reported and they just don’t follow up on it or have interest. If it was something with the cities underground tunnel/piping network (especially likely if it was an in-ground tunnel) it could have been something going on in the entrance/exit to the tunnel system, or there could have been a severe gas/water/etc leak in that area.