After reaching a certain rank with Ryuji (8, I think?), he gains the ability to have a chance to insta-kill an enemy when you Ambush them.
While traversing Mementos, this happens quite frequently. I know that it normally gives me the mask of an enemy I would've had to fight (it tells me I can't carry another mask most of the time), but is this giving me any experience? I'd hate for all these insta-kills to be causing me to miss out on experience.