User blog comment:SomeoneYouUsedToKnow/SYUTK's V5E11 - Being Weiss Is Suffering - Impressions/Recap/@comment-26018514-20180104034439/@comment-25936766-20180104142845

1) Weiss still needs to stay still to Summon anything, however. Even if she made the Summoning Glyph somewhere else, Vernal would've just ignored it and attacked Weiss herself before she manages to summon anything.

I do think that she could've tried to summon the Boarbatusk instead, since it summons quicker than the Knight.

2) There was only 1 door, IIRC. The exit, which Hazel was guarding. Unless Vernal can make herself invisible or teleport, she would've been seen leaving and that would've been seen as deserting the villains, which could've led to any number of things.

And of course, I doubt Adam and the WF know about Vernal and Raven, so if Vernal leaves she would inmediately be seen by the dozens of WF mooks, and Adam.