You can have the ternary return a closure that would perform the requested function
$func = $a==$b?function(){ print "33"; doThis("TRUE"); }:function(){ print "FALSE"}); );
$func();
or borrowing from javascript you can create a IIFE (Immediately Invoked Function Expression)
$a==$b?call_user_func(function(){print "33"; doThis("TRUE");}):
call_user_func(function(){print "FALSE"; });