Gwen would recognize that cloak anywhere. Especially paired with that salt and pepper haircut. She would have thought Sodder would wait until they're all back in Deerington to bring new people in, but guess not. Being on the Titanic didn't stop new people from arriving, why would being in Rapture be any different?

"Dr. Strange! Hey!" She rushes up to him, quickly realizing he's got one of those gross spine-burrowing bugs on him. "Yeuck... Want me to get that off for you?"

She may or may not have an understanding that this isn't the same Dr. Strange who helped her out before.