Fall back option on dual pool GSLB, confusion!!

Hello, I have a dual pool GSLB, primary pool has 2 servers with load balancing method as "Global availability/ Global availability/ fall back IP4 as preferred, alternate and fallback methods" similar setup is configured for secondary pool, my fear is that because of the fallback method, even if all the servers are down from primary, it will never fail over to the secondary pool,

can someone shed some light on this ?