9-1-1 fans saw Hen Wilson (Aisha Hinds) step out on her own in season seven episode two, after she felt betrayed by her colleagues Eddie Diaz (Ryan Guzman), Howard 'Chimney' Han (Kenneth Choi) and Evan 'Buck' Buckley following an incident with a drunk driver.
As the episode came to an end, Hen ignored a call from Chim as she trusted her instincts and set out to discover what had happened to the cruise ship carrying Athena Grant (Angela Bassett) and Captain Bobby Nash (Peter Krause) – and that discomfort between the crew back in Los Angeles will carry through for a whole, says Oliver Stark, who plays Buck.
"It is one of the first times that there has been this kind of friction, and Hen is a character who all of these characters respect and look up to so it's not usual for something like this to have happened," he told HELLO!
"I don't think it's going to be negative for too long but there's some tension and it is certainly going to carry through for a little while, and not be brushed over too easily."
9-1-1 returned to screens, after a ten-month break due to the WGA and SAG strikes, on ABC after moving networks, and episode one had the difficult task of introducing these characters and their dynamics to new viewers, while also keeping the longterm fans invested.
"It was really lovely to embody these characters again, and I love the side of Buck that we got to show; that he was caring, that he got to be there for Christopher and impart some possible wisdom on him, and he got to be the courageous Buck we often see on emergencies," Oliver shared.
"I'm proud of the character that he's become and I was happy that we got to show that off in the first episode."
As for what comes next – episode three will bring to a close the three–part emergency that saw Athena and Bobby's cruise ship attacked by terrorists before a bomb exploded, and will bring together the 118 for the first time all season.
"Bobby and Athena are going to be put through it independently of the 118 for a good while, which I think is really cool because they are such iconic characters and they get to be there for each other without outside help for a long time – and it's going to be fun, certainly for me because I wasn't a part of those scenes, to get to see that play out!" said Oliver.
"But then once we move into the period where the 118 do arrive, that for me is the heart of the show, that found family, so that reunion will be very meaningful and a fun watch."
Episode three will also reintroduce longtime audience members to Tommy Kinard (Lou Ferrigno Jr.), who worked at the 118 in the days before Buck arrived, and has an off-screen friendship with Chim.
Viewers will recall, however, that Hen and Chim both dealt with racism, xenophobia and misogyny before Bobby arrived as Captain, and Tommy was a part of that crew who didn't put a stop to it.
"Tommy has a great relationship with Chimney [now] but obviously there was a lot of tension and some very questionable decisions by Tommy in the 'Hen Begins' episodes," said Oliver. "I think we've tried to show a story where he's been able to move past that and learn his lessons and realize that maybe he wasn't the instigator in some of those instances but was just unsure of how to step outside of it."
9-1-1 airs on ABC on Thursday at 8/7c.