Hmm... I was getting ready to post the exact same message as Timbo did, but then I remembered you had an Angel in the tank.
Nitrite is one magnitude less toxic than ammonia. So one could say that, everything being equal, if they survived the ammonia spike, they could probably survive the nitrite spike.
The only problem here is, everything is not equal. The bacteria that convert nitrite to nitrate reproduce slower than those that convert the ammonia to nitrite. So it typically takes longer for the nitrite to spike and fall than the ammonia. Also, the fish (angel) is probably already stressed and damaged from the initial ammonia shock and now is going to have to be put back through the "chemical soup".
If I were you, I would do the 25% water change. At least that would get the nitrite down a little. Your tank will still cycle fine.