Get stuck in the corner, connect the two shown points with a screen-wide crosshair, then jumpthrow.

To get out of the window through the smoke you need to do the following steps:

1. Jump on the lip in window.
2. Shift-walk slowly until you hear yourself dropping (on the edge outside window).
3. Then hug the wall by pressing S and D and jump to get up on the tiny lip.
4. Kill all enemies.

This video explains it further