> If somebody was too impatient and manually removed a resource that was managed by CFN, then he might end with a deadlock, where only help was actually a support team member.

This specific situation can be resolved by doing a 'continue update rollback' and skipping the already-deleted resources- see the troubleshooting guide [1] for more detailed info.

[1] https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGui...