1. King Ezekiel's men are ambushed in the forest after they hear a menacing chorus of whistles.
We've heard those whistles several times over on the series.
It instantly brought to mind when Rick's group was ambushed in the season six finale.
Rick and the crew were stopped by bright lights and eerie whistling.
When Rick was trying to bring Maggie to the Hilltop, his group was surrounded in the forest by a chorus of whistling Saviors. It eventually led to the death of Glenn and Abraham.
This time around, Negan wasn't there to take out anyone with a baseball bat. Ezekiel and Carol also had the upperhand by anticipating the ambush and took everyone out as soon as they surrounded them.
2. The title of the episode "Monster" has a few meanings.
Gregory is one of two people to mention the word "monster" on Sunday's episode.
Rick and his group have referred to Negan's men as "monsters" several times over since they killed Glenn and Abraham and countless other allies. On Sunday's episode, Gregory outright says they are monsters when he begs to be let back in to the Hilltop.
However, Morales calls Rick out on Sunday's episode and tells him he's no different after seeing him brutally kill a newborn's father.
"I guess we're not the same guys we used to be, huh? Because you're a monster," Morales tells Rick.
It's also a callback to Jessie's son, Sam, from Alexandria.
Sam was terrified of the "monsters" that lurked outside. Imagine how he would have fared with the living monsters.
Before he was torn apart by zombies in season six, Sam referred to the undead as monsters.
Carol even threatened Sam in season five and said she'd take him to the monsters if he ratted her out for sneaking into Alexandria's armory.