Killing the 0-4 laner again vs collecting Bounties, atleast that's most likely the case here.
Also Sneaky's Mythic (Galeforce) has it's power mainly in its active that he already used and Graves' Mythic (Shieldbow) passive was still up (and also stronger IMO). Then there is also the fact that Sneaky bought a PD + Cloak, which are very shitty damage items.