After I discovered wall clipping I found this trick and now I found a good setup that saves time so it is pretty good and Ethan doesn't take damage. So after Ethan clips the wall keep pressing to go ahead to not take damage.
It is a trick that can be easyly performed when you call elevator after time for Dilbert entering ends and before elevator closes. It's easier on the first floor of the leves because you can't go down and you can call elevator with down arrow key. If it works, the elevator will go down and opens the times you called it, if you called 6 times, it will open 6 times, but it's possible to call just once.
This trick allows a faster execution of CIA rooftop escape. Just go on the higher box, wait for the guard going left and go down. When Ethan is about to fall, use the bomb. Try to go as close as possible to the right so you don't get caught by the guards but watch out for the laser. So Ethan will keep standing even after he falls and you need to go behind the door and shoot the guards and you can complete the level. It is a little difficult trick but it's just a matter of practice.
You can do it only on the lasers floor. It's basically take laser damage with Ethan's back to the wall and he's gonna ignore the wall physics and go directly to the camera boxes. It really saves a lot of time.
First you need something that Ethan can climb like a box or wall and start side walking and when Ethan is about to fall press A button and then he will fall and climb into nothing. In CIA rooftop you can skip an item using with this, but I don't know if it's faster. There is a video for example: