There are two elements that make this passage read like an eyewitness account. Firstly, the use of the present tense for the verbs in Mark 7:32. A literal translation of verse 32 would be, And they bring to him a deaf man who spoke with difficulty and they beg him that he may lay on him the hand.
The second element is the use of the Hebrew or Aramaic word “Ephphatha” (see Mark 7:34). As Peter was an important source of information for Mark, this probably derives from Peter’s witness of the healing.1
31 Jésus quitta le territoire de Tyr, et revint par Sidon vers la mer de Galilée, en traversant le pays de la Décapole.