Is marriage to a prostitute, in the presence of two witnesses from the building's staff, and with the intention of divorcing her after traveling, Islamically valid?

Marriage is a great ritual that Allah described as one of His signs and a solemn covenant. It should not be a subject of manipulation, especially since it concerns private parts. If a woman marries herself without a guardian (wali) or witnesses, the contract is invalid by consensus. However, if it is with two witnesses but no guardian, it is a dubious marriage (zawaj shubah), concerning whose invalidity there is disagreement. You must initiate sincere repentance.