[quote=@Prince of Seraphs]
Is it truly necessary to make Hopper think the Immortal killed Revel in order to get him to kick the guy. Couldn't we just ask Hopper to kick the Immortal really hard into the Reactor Pit?
[/quote]

Probably not, but Hopper has both a defeatist streak and a sympathetic side to him according to his personality.  Revel doesn't know the fullest extend on this, but he saw the moment that Hopper said "There's no way" and made a gamble from there.  If anything's going galvanize Hopper out of "there's no way" it's the perceived death -or just perceived injury, perhaps- of a teammate in his name.