When the blackscale fell before his axe, Grimmgang immediately went for the second one, sacrificing safety for speed. It's defensive posture clearly indicated it was stalling, and Grimmgang wasn't willing to give reinforcements the time to arrive, even if he had to take a hit for it. Once he was within the guard of the lizardfolk, he delivered a brutal overhand chop at its chest with all his strength.
Spoiler
so it didn't change position, right?
Move to H11, running start
Swift: jump to I13, autosuccess
Tumble at full speed to avoid AoO
(1d20+13)[20] DC25
I could have sworn I had +14, so that last turn was no autosuccess after all. Failed on 1
(1d20)[10]
Standard: Mountain Hammer
Attack
(1d20+8)[25]
Damage
(1d10+4)[13] +
(2d6)[6] +
(1d6)[6] skirmish