Basically just a much more optimized version of my 44 second run. Instead of leaving through the window at the end, I just run through the doors on the way there, and instead of killing the guard, then throwing the grenade, I go grenade the door as fast as possible, then get the shotgun and kill the guard, and when I go back to the basement door, It'll already be gone, instead of just throwing the grenade then, and waiting a few seconds. It's probably possible for a 34 second run, but I'm not going for it.