It's silly Iknow, but I have this problem...
When you need to blow up the warehouse, I came from behind, used the ladder to get to the grids above the main hall, and got all the way to the office.
But after setting the bomb i cant find my way out in the 2 minutes...
Im kinda stuck...
One way is to go out the back door, you will have to fight one vampire as soon as you get to the door. After defeating him head along the building until you get to the alleyways. You will come to another locked door that will not open until you defeat the second vampire. There is a way to get between the two boxcars and avoid the second fight. Then you just go through the railway cars till you get out. I always clean out all the opposition going in so the only fights left going out are the two vampires. These are not paritcularly tough fights so you should be able to defeat both vampires and still make it out in two minutes. Good luck