I’d be good with my character dying that way so would plenty of other groups. If that’s how the group rolls then it’s cool and from what little info we have it seems like that’s the case here. I expect that assassin to have the same advantages as me. I’d really hate the assassin running all of those extra checks because then I’d expect to if I was an assassin character. If the dm wants me to spot it then just decide the Assasin fails the check and quit pretending you aren’t fishing for a role. Sometimes characters die from bad luck. I’d actually be annoyed if the cleric got that random reaction out of nowhere. It’s basically retconning.