That was fast.
He's a killer for sure- but he does follow orders.
And Shinji would (initially) want them alive, because Shirou is his Bro, and he wants to fuck Rin.
If it goes the way of canon where both of them tell him to get fucked however? Then he'll send Shuwen to yank Shirou's spine out and bring Rin back for RAEP.
Basically the issue is that nobody has a way to actually detect Li Shuwen; Saber might manage to dodge his first strike on Instinct but that won't help Shirou.
So basically all those scenes in the VN where someone runs up to Shinji and punch/grab him end with everyone getting wrecked by the non-magically invisible punchman.
Ragnarok, come day of wrath
That fallen souls might bear our plea.
To hasten the Divine's return.
O piteous Wanderer.
Skitter gets by in Worm due to massive plot shield and somehow nobody in that universe being capable of feeling when they have bugs crawling over them.
Ragnarok, come day of wrath
That fallen souls might bear our plea.
To hasten the Divine's return.
O piteous Wanderer.
It's not. There have been several characters who didn't know how their powers actually work. Eidolon being the most obvious example. They just instinctively know how to activate them to some extent.
That aside, Skitter's powers were plenty analyzed by people who would have noted that.
Ragnarok, come day of wrath
That fallen souls might bear our plea.
To hasten the Divine's return.
O piteous Wanderer.
Shirou Emiya summons Seryu Ubiquitous. Justice Bringers Unite!
Isnt it obvious? He'd be COVERED WITH BEES
What if Caules summoned Ramesses as the Rider of Black?
Ramesses' crushing ego and obvious mid-boss factor would make him die way early to stupid shit, unlike Astolfo.