Read the extract from when Dr Lanyon witnesses Hyde turn into Jekyll and answer questions 5-7 below.
He put the glass to his lips, and drank at one gulp. A cry followed; he reeled, staggered, clutched at the table and held on, staring with injected eyes, gasping with open mouth; and as I looked, there came, I thought, a change - he seemed to swell - his face became suddenly black, and the features seemed to melt and alter - and the next moment I had sprung to my feet and leaped back against the wall, my arm raised to shield me from that prodigy, my mind submerged in terror.
How does Dr Lanyon feel about the experiment in this passage?