At first set the loop, to work perfectly. No matter you can stop it or not.
I guess you have to apply a little delay, before goto. Depends on how long is your choosen animetion you want to loop. (I you maybe do not know delay: it is in secs, a four sec delay looks like
~4).
You have to try to use 'playMove' command as well.
When you loop an animation, it can happen that OFP 'remembers' all of the given command by the loop. You can imagine it as a buffer, which records all of the commands and execute the new command only when the last looped command is executed. In my experiences...
So when you got the endless looped animation, you can go towards and insert the condition which can brake the loop.
Make sure this variable is set to false in the init field. And this variable (you named 'go' now) became true by a trigger 'on activation'...