User blog comment:Willbachbakal/Singleplayer Plasmids: Scout/@comment-1999649-20110825134626/@comment-1330314-20110826102614

The problem with that in a singleplayer setting would be that you could easily get lost inside the map if you could go inside the scenery, and if you phased out in the middle of it you'd either glitch horribly or die as as a safety mechanic, neither of which are particularly pleasant.