So, I know this is a bit of a necro on the post, but I feel like an update is in order in case someone missed the new information or stumbles upon this now, like me- 1. You can indeed drink certain types of radiolaria (inert types) without turning to Vex, like the Guardian does in Riis-Reborn. It stil transmits a signal, which might just be picked up by Drifter's ghost since it was modified by him to hold both light and darkness, which he then might percieve as a voice. 2. Technically, in the current dawning and the previous one, we kinda spiked a few of the vendors with Vex Milk as well... They seem fine but who knows XD 3. I think Drifter found a way to cook it, but it was a bet on his side because he himself isn't sure if it actually nullifies the effect, as evident from one of his Vex gambit quotes. If he didn't actually drink it before, he clearly will eventually. He's not one to shy away from eating a sentient being. 4. Kabr didn't have his ghost, while Asher's ghost is corrupted. As long as Drifter's ghost is not corrupted by the radiolaria (pretty sure radiolaria can't even corrupt that one, since Drifter's ghost is, again, modified to hold darkness). If he starts turning into Vex all he will need to do is shoot himself in the head and come back normal. On top of that, I can't entirely confirm it, but I'm pretty sure Drifter has his own ascendant plane, which should nullify the Vex effect as well, since the Taken and Darkness have been shown to overpower the will of the Vex.

I’m just glad coffee still exists 🤷‍♂️

That would have to get in line behind all the other diseases he would have from everything he’s eaten

"My Grandma got a Malfeasance"-Drifter

Now that I think about it.....one of the Dawning ingredients we gathered was Vex milk...….huh

He gunna turn into a iron man version of a guardian

Maybe he filtered the vex milk somehow to take all the conversion stiff out? The drifter is pretty crafty, especially with food and survival stuff, so i wouldn't be surprised if he did.

Ya know if you defuse the bomb you can sleep in the husk of a hydra?

In the tapes from the allegience mission (assuming they are true) he states that ghosts push guardians to become more power so the ghost has a stronger connection to the traveler (light). With the Drifter's long, "worldly" life could he have a connection so strong that the ghost can heal through corruption?

He also eats hive knights

Possibly. Some things can resist conversion. The Taken for instance. While Asher says they are susceptible, all evidence points to the contrary. Paradox Heroic and the BoS. Both showed long term exposure of Taken to the Vex have no side effects. Also...we’ve been exposed to the fluid quite a lot with no side effects. Kabr was in the Vault of Glass, the rules are different there. Likewise Asher losing his arm was under unusual circumstances that also involved his Ghost being altered. I find it noteworthy that Asher has yet to die and be resurrected since he lost his arm. As his Ghosts alteration makes him concerned of the results. The Drifter is also a notorious liar haha.

He's whispered quite a few interesting lines to himself. If he's saying them to himself its less likely to be utter BS so its quite possible all the stuff he's saying about the Nine trying to "fry his brain" and this Vex thing is at least partially true