2nd Mizukage vs. 2nd Tsuchikage: What Happened?

[Moe22]

It was either a jokey boy explosion caught both of them(unlikely), A dust release caught both of them (less likely) or some sort of mutual death jutsu, such as a version of two headed snake mutual death (anko) or RDS (minato/Hiruzen) (more likely)., or they both exhausted their chakra after going through jokey boi and jintons (most likely)

Yeah, very plausible. We know it came down to a tie because they found ways to counter every jutsu thrown at them!