Use マシ to suggest acceptable/better option given two undesirable choices. English equivalent of the given Japanese sentence "ミチルさんは[一人]でビクビク歩くよりクワノさん[と]でも行った方がマシでしょう?" will be "No one wants to walk with Kuwano-san but doesn't it beat walking alone scared?" In other words, both walking alone and walking with Kuwano-san are not great choices but walking with Kuwano-san at least will provide sense of security.