What

Can't. It only goes to the owner/sender.

how about if I tried to send it to myself? what setting do I need to enable?

@G You're looking for the sandbox email options Setup > Company > Email Preferences (Email Options tab). Make sure you're selected appropriately (either send email to specific address or send email to logged in user). Assuming your settings there include you, you'll get a copy of any email that is sent out from sandbox (whether it was "supposed" to go to you or another email address). My guess is you have this set to "Do not send emails". As @Rich Keller was alluding to, sandboxes will NEVER send emails directly to any email. It will ONLY send emails to addresses referenced in the Sandbox Options settings.

ah yes, another admin changed this setting literally an hour ago hence it wasn't working... thanks @James Morris & @Rich Keller