Basically, there is no strat. I just do it like normal mode; mine should be able to go to about 1:15 since I have to shoot all the guys at the end with the sniper rifle...I did really crappy on my 1:24 run, I'm sure I can get at least around 1:17.
Which reminds me, I was going to try to improve that...
And, I was going to complete SA/PA as well...For PA, shoot the far away sniper, both tards behind you, and then the guy on top...go right, shoot sniper, go to side of stairs, shoot guy, switch to unarm..punch guy right inside for Obj. 4, then turn corner and punch this guy if you want, or just open the door to the stairs. Take the basement safe; on a good run you could kill everyone and probably be out before 1:40 I think. I haven't made it all too much further...The furthest I made it was the bottom set of two hackers, I ran in there and they both saw me, I punched....One died, but the other one still decided to shoot me with a rocket at point blank range...