#Each line of $text is independent of the other and not joined as a continuous line.
$text = 
q~
adfRadfaUYBGsQWERaeYETEWoyMSn
nbPOIVcRCVVfOOPQbHbnRIIqWweRT
~;

$result = "";

while( $text =~ /[a-z]+[A-Z]{4}([a-z]{1})[A-Z]{4}[a-z]+/g) {
   $result .= $1;
}

print $result; # prints sc but should print scf