all you need to do is open the console and and turn on sv_cheats the type physcannon_mega_enable 1. then you can pick up most of the NPCs in the game, this excludes most of the main characters in the game. also, when you pick up any allied NPC they sort of get "cloned" they're still standing there but you have a ragdolled version of them in your gravity gun. (NOTE: this does not seem to work in Garrys mod and may only work on the orange box version of half life 2)