To see the output of that, you can either put that in your theme/functions.php or i would say bp-custom.php in dir /plugins/pb-custom.php i saw that simular code of yours on stackoverflow.
Not sure what you are tying to accomplish with that s2, but the issue is probably not that piece of code, but more trying to get the right levels.
That code all it does, is checking usernames, so if username is “fred” it will remove the bp_core_record_activity but not according to levels. You need to figure out a way getting it to print out the levels. and then do a if or else statement per level.
