Sleeping with the Girls/WMG

The SI home universe isn't Real Life, but the Haruhi Suzumiya's

 * And the SI is one of many Sliders that have come into existence and has a serious case of How Do I Shot Web?.

The SI is going to find out that he's in a self-insert fanfiction.
And he'll be really angry at "himself" for what he's been put through, but won't be able to figure out what to do about it.

Bernkastel is dicking around with the fragments.
She's bored and thinks that dropping an oridinary human into apparently fictional worlds could be amusing.

The reason why Walker can't be affected by magic.

 * His spiritual capacity is immense, but empty. All the magic/ki attacks he's received so far are roughly comparable to drops in a bucket.
 * To clarify, everyone from Walker's earth would be the same. The laws of physics act as a form of Training From Hell, constantly suppressing everyone's magic. This is similar to what Nanoha's Training From Hell when she constantly had Raising Heart suppress her magic. In a couple of of years time, as his body adjusts to the new environment, he's going to have a heck of a magic capacity, if not necessarily the skill to use it efficiently.