To answer your question 'why' well G-Man's acctuall name is sarge Funk and the reason he is always so depressed is because a higher power stole him from the 60's and changed his name his only outlet now is to frolick in the trees... and as for barney... well... hes jut...ye...
*stares blankly at Sparda*
Anywaaaaaaaaaay, I have done one similar on DM_Overwatch with Breen + G-Man holding hands, while skipping of the edge of the central building. I also have no life.