I wouldn't do that. If Adam doesn't know it, don't let the reader know it.
If you have ruined the surprise, any suffering and fear Adam feels as he thinks he is dying will be lost on your reader. They already know he can't die.
When you write that scene, there will be zero surprise, they will just skip forward to find where Adam figures it out. They already know what is coming.
If you don't tell them, they will be wondering how Adam gets out of this, he's been stabbed in the heart,or his throat's been cut. Or even if Adam gets out of this!
They will be intrigued. Then they can identify with Adam when, to his surprise, he doesn't die.
Readers tend to identify with the protagonist, in a 3PL story (with one protagonist) you should never tell them anything the protagonist doesn't know. They should learn with them.
Once the narrator goes "omniscient" (in this case not only telling them something Adam doesn't know, but telling them the future as well), they know the narrator is capable of that.
That's the whole problem with omniscient, it feels to readers like a cheat if the narrator knows a secret and doesn't tell them. Omniscient narrators make it much more difficult for characters to keep secrets. Like they are a traitor, or secretly the birth parent of an adopted protagonist, or whatever.
This is just my opinion, but if Adam doesn't know, the reader shouldn't know, and teasing the truth will not make the passage read better, they will already know what to expect: Adam gets in trouble, he gets killed, he thinks he is dying but he doesn't die, blah blah, where does he figure it out?
They won't identify with Adam. Even though readers start out more than willing to identify with the first character they encounter. You will sap all the energy out of this passage.