Non-muslims in the afterlife

Salam alaikum. I have a question. I know that people who have never heard of Islam, or have only heard about it incorrectly, will be put to the test on the Day of Judgment. My question is this: why does a non-Muslim who perhaps received the message of Islam but did not distance himself from his original religion, but who behaved well in this life, go to hell, while instead perhaps a rapist (for example) who has never heard of Islam will be given a second chance? I know that Allah is merciful and does not commit injustice.