also he doesn’t blame sirius, they just didn’t expect for severus to actually go there. that was the whole joke. i already talked about this but honestly, how dumb was snape in that moment???
james potter ran out to pull severus snape from the shrieking shack with one tought in mind: remus lupin.
because he didn’t believe remus should be held accountable for what might happen if he is too late to protect him but it’s fully aware that he will be.