This is such an edge case I am not super enthused about prioritizing, especially since admins usually have 2 devices and can just switch to Phone if they messed stuff up. Or even just SSH in and fix via console.
You are describing a security hole where a moderator goes rogue and blocks admins, however they do not escalate privileges just make life a bit more annoying for admins.
Giving admins a free pass around screened ips is not going to happen.
I am sort of open to having a sanity test that makes sure you do not block yourself when blocking an IP
I am open to possibly making an extra sanity test that makes sure no staff have the IP to the best of our knowledge prior to adding an IP or range.
Moving this to feature request, I do not see this as a bug.