Leela had taken advantage of the flickering to get riiiight behind Shawn. Which allowed her to kick his legs out from under him, yank his head sideways, and slip something into his ear with a canteen.

"Of course it's not supposed to happen. Just like you ignoring me wasn't supposed to happen. Jesus Christ in a Sunday dress, I went through that crying act to get one of y'all close for nothin'."

She drops Shawn to deal with his little problem by himself, and pulls out her scythe and chain.