Mk 1:8, is not telling us baptism is not necessary. Only that the Holy Ghost is at work as well.

"Buried with him in baptism, wherein also you are risen with him through the faith of the operation of God, who hath raised him from the dead." Colossians 2:12

"Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life. ... knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin." Romans 6:4-6

Yes people run out and find your baptism, I did!