Singular squad ungas over the river, benos could swarm the ungas that carried all the ap(which does less damage than standard to younger castes). Instead, they were adamant on waiting for their 15 minute safety net. Benos start losing numbers, still won't guerrilla flood the one squad(at this point they lost the opportunity to). Xenos often forget that there are burrowed larva and don't want to risk their lives to stop a single squad rush. Marines don't care, they'll give up their lives even if it means losing defibs.
The other squads come in, immediately rush the river due to command orders. Every squad is in the caves. That single order saved the delta(soy) boys and ended it.
So, to recap. It wasn't that early rush that ended the hive. The Queen deovied fast, the hive was afraid to swarm the squad, and they were waiting on their aging safety net. You want to fix the issue? Tell the moderators to stop letting marines rush the planet at 12:15 then proceed to send all the other squads into the caves. THAT was pretty damn meta, no FOB, just go assist delta north of hydro.
Also, if I remember correctly, a xeno is supposed to be worth three marines. What happened there?