I really don't see Miria "catching-up" to Hysteria as Miria being faster, so much as Miria planned to intercept her in the first place.
AKA: They grab Anastasia and run away with her, Hysteria chases them.
Miria, expecting this, was already headed to cut her off before she actually got moving.
That is what makes the most sense to me, but some people would probably rather ignore that and continue to complain about speed differences.
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I also get the feeling the game plan is to drag Hysteria into Cassandra vs Roxanne and have all three of the new Abyssal Ones at each others throats.