For instance Interval 2 if your on fearless and going for the chopper if the boss guy hits you with a few melee attacks you will fail >.<
Also, i have noticed during interval 5, during the phase caster or power armor fight that superhealth is also given to one, or the other depending on when you engage superhealth.
I didn't use the trainer until that level and I never had a crash until i tried the trainer.
Trainer options also, as others have posted, do not seem to work regularly and have to be disabled and re-enabled quite often for them to work.
the game do indeed crash randomly when trainer is active at the end of a level, But the diyng part i do all the options twice and no problemos and also switching weapon need to do the unlimted and the no reload twice:
that is pressing twice on all options to get the super health and so on.
hope it helps a bit
firewall and other security software.
on trainer and game.
version and distribution.