yes, last exits the innermost enclosing loop.
this is from perldoc perlfunc(ran from the command line):

The "last" command is like the "break" statement in C (as used
in loops); it immediately exits the loop in question. If the
LABEL is omitted, the command refers to the innermost enclosing
loop. The "continue" block, if any, is not executed:

 LINE: while (<STDIN>) {
                last LINE if /^$/;      # exit when done with header
                #...
          }
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