Rex instantly bolted upon finishing taking care of Arnulf, he didn't idle knowing that despite his increase in strength he doesn't really know how much stronger he actually got. It's also his first time activating his King Mark, there might be a limit.
Despite the escaping Ruston and Ian are hurt badly, but they are still Alphas.
Comparing them to normal Werewolves would've become the greatest understatement, their speed is quick enough to cover a mile or maybe more from one leap. From the conversation he needed to have with Giana alongside taking down Arnulf, it's unclear how far they get during that time.
While dashing through with incredible speed surpassing his imagination, Rex opened his stats.
<Rex Silverstar - Banished Dark Moon King Mark>
Pack: Silverstar (5/5)
Level: 51 (46,373,500,000/54,000,000,000)
Race: Exalted Royal Black Werewolf
Full-Moon: 23 Days - Ice and Snow Moon
Berserk: 71%
Sanity: 40%