Whelp, scans it is then.
Drain is a passive Absorption upon activation, and I will say this, don't ever follow the wiki page which is intensely outdated.
Here's the move at 1:10
https://m.youtube.com/watch?v=30aNmF-YnC0
Now as you see here, the move itself does drain the opponent, but the opponent itself does not get drained by a vector. It drains the body and shuts it down, and then after the body gets killed, it goes to Cole.
Accel can't manipulate a vector while dead, that's an obvious NLF, on top of this, he's shown manipulating Absorption even if it did have a vector.
Also, for the record, Bio Leech and Ionic drain are completely different moves mechanic wise, and they have entirely different uses.