$out is an array so just grab strings at indices

Examples.md

@@ -18,8 +18,8 @@ fe() {
 fo() {
   local out file key
   IFS=$'\n' out=($(fzf-tmux --query="$1" --exit-0 --expect=ctrl-o,ctrl-e))
-  key=$(head -1 <<< "$out")
-  file=$(head -2 <<< "$out" | tail -1)
+  key=${out[0]}
+  file=${out[1]}
   if [ -n "$file" ]; then
     [ "$key" = ctrl-o ] && open "$file" || ${EDITOR:-vim} "$file"
   fi