If a colonist is in a MOOD and won’t respond to commands you can get around it by selecting that colonist and another colonist and instructing them what you want the colonist in a MOOD to do. Then just get the second colonist back to working on his/her original job.
Someone else already found this bug and I fixed it for Alpha 8. Not sure if we’ll back port the fix to Alpha 7 as it’s not critical. Enjoy the exploit or play fair, depending on what experience you wanna go for