It's close to impossible to not crush on Vash, period XD.

Only in the manga. The anime version's pretty sexless if you ask me.

I think it's interesting that it's Meryl who approaches Luida there, not Milly. I mean, Milly's the more emotionally forth-coming and understanding one, so how come she hangs back and lets Meryl do the talking? I'm betting Milly has sussed something out.