You didn't kill your plant. It's just going to need a bit of TLC until it puts out new roots. First thing I would do is cut off that flower spike. Keep it in a shaded place in high humidity so that it doesn't dry out by transpiration. Eventually new roots will appear. You could try some rooting hormone. It has worked for me before. I dusted the base of the stem with the hormone and gave it a light mist and left it alone.