Unable to access fields with [ ] characters in ruby filter

Sometimes it is useful to access fields (or nested fields) containing [ or ] characters in the name. Currently I am unable to access it even if I try to escape it.

For example I am unable to remove or set a field "myfield[with[[".
ruby {
code => "
...
event.remove(k)
....
"
}

I think event.set and event.remove should be modified to allow better access to fields, even to fields containing [ or ].

Logstash version: 5.2.1