Aaron has reported in the forums that after launching the TKL WordPress appliance there was a 'Verify Admin Email' notification and the admin email is still admin@example.com (the default we set at build time).
Until the issue is fixed, you should be able to workaround it by manually setting the email via the turnkey-wp command (wrapper around wp - the WordPress CLI tool). This command should do the job:
turnkey-wp user update admin --user_email=NEW@EMAIL.COM
Please see my forum response for details for more details.