[plt-scheme] aborts, composable continution, and begin

Is this correct behavior?

(define (foo)
  (call-with-composable-continuation
   (lambda (k)
     (abort-current-continuation
      (default-continuation-prompt-tag)
      k))))

> (begin (foo) (printf "I fooed!~n"))
> ((lambda () (foo) (printf "I lambda-fooed!~n")))
I lambda-fooed!

It seems that the continuation is lost in begin, but not in the
application.

-- vyzo