That very much does not seem like M. As both LLENN and Pito point out they're acting especially incompetent. He shouldn't need a bullet line and just generally has been fighting very poorly. I'm inclined to agree it's a decoy he hired to pretend to be him. If we want to get really paranoid here, while he did use a similar seeming sniper rifle in SJ2 - it was borrowed from Pito and a slightly different model number than what is shown in the ZASKAR Shop. Pito may still have the original in her arsenal here and either way that wasn't M's primary weapon to begin with.
As for what he's doing if that's the case... I suppose if the idea is to trick us into thinking that's M the questions would be "how/does he expect us to deal with him?" and "where would he want to be to take advantage of that?" You can kind of unify those with the convenient buggy if you assume something like "Hope the team thinks they can take the buggy to charge up the slope to his position, but have the buggy's engine sabotaged so he can kill it at it will so we're stranded on the slope" in which case... I don't know, maybe he would prefer to hide in the District and only reveal himself to snipe us after we've left with the buggy (or just skipped it and headed to the cliffside?) I'd say the Forest is an option too as a likely ambush point because it's another logical place we might choose to go to avoid the decoy's sniping.
Back to the buggy and if it's sabotaged... I do think something like having a remotely triggerable device that cuts the engine or something makes a bit more sense than trapping it to blow up... if it was right next to Pito (True). I think if it was there then making it (extra) explosive would be too risky for him if it ended up blowing up near her if the fight with Erlkoing landed it in the crossfire. Though if it was some distance away then maybe - IIRC there's some flavor text in some of the LN talking about trapping vehicles in such a manner as a reason to be wary of using them though as far as I've read (like Volume 6) I don't think anyone has
actually utilized that yet.
If I were to take a guess here at M's plan, he's hiding in one of the
District crates, possibly/probably using a Drone to surveil the battlefield remotely to figure when and how he should make his move - though he could use comms with hired help to do something similar and is waiting for us to either: fall for the bait of the
Cliffside "M" and then come out "behind" us to catch us in a pincer - ideally when we're on the
Slope, run to the
Forest to gain cover from said decoy where he may have additional traps/allies set, or if we stick inside the
District... you know, I'm not sure what his plan would be then, it might be the most inconvenient for him if we did that, but would allow for his decoy to keep firing on us.
Then we can go a level deeper and wonder if the
Cliffside "M" being
so incompetent is because he
wants us to see through that ruse and think along the lines I just described and there's some extra layer to this but I'm not sure I see the advantage to that - him actually faking the incompetence before "getting serious" seems way too risky, because even if we conclude it's not M it's still not the worst idea for us to try and get rid of a sniper.
Also P-chan is the QM's favorite AGGO character.
just the best
But
we should not be letting LLENN listen to her right now, IMO.
In a way, I think having Pito (True) in/on the buggy is a fairly good defense against the possibility of it being trapped explosively. I do think we should have someone try to heal her - her dying is a fail condition, we're told Erlkoing can drain, and I still want to test my theory that healing Pito (True) and taking her further away from "death" might weaken Erlkonig. If you think about it, us attacking Erlkonig!Pito and taking it/her closer to the brink of death is kinda what she wants. I think it's
plausible that full healing Pito (True) could be an out-of-the-box victory condition - and the health drain Erlkonig has is its way of denying that.
I wonder if the
Warehouse might be the ideal battle location provided it is covered from obvious sniper fire. M surely would have considered that kind of contingency but what he could actually have prepared there (like explosives) may be limited given Pito (True) started there? Of course that would mean Pito (True) would be in close range to Erlkonig.