How does MX work in this situation?

[wruegg]

Forgive if this question reflects a profound misunderstanding of the
subject matter.

Here's the scenario. Inside my firewall, I attempt to pass 2 messages
via an SMTP client to mail.foo.com on port 25. The client does not
perform a dns lookup.

"mail.foo.com," however, is actually an alias set up in my DNS MX
records. e.g.:
mail.foo.com         MX      10      sendmail1.foo.com
mail.foo.com         MX      10      sendmail2.foo.com

What will happen to the messages?