why would you want to put a video on loop?
I'm guessing you are wanting it for the startup of the game until the player skips it with esc to get to main menu?
Not 100% sure but try creating a condition "intro_skipped" set to false
& then in game start action or at begin scene action - wherever you set the video playing add action parts...
if 'intro_skipped' is false
play video 'video name'
jump back 2 action parts
actually it might be a good idea to add this inside a called by other action block.
In key input Escape (release) add...
if condition 'intro_skipped' is false
change condition 'intro_skipped' to true
I can't say that it will work mind & I'm not sure if videos pause actions in the action part list while playing or not & I'm also not sure if pressing escape will trigger key input actions while video/cutscene etc is playing.