When the list gets too long, I like to use awk to comb through the list and kill anything that is found. It's easy to search and parse out the tokens like so:
ps -ef | awk '/behat/ {system("kill -9 " $2)}'
ps -ef delivers a verbose list of processes. This is piped to awk where I can specify a command using awk's scripting language. In this command, I first search for 'behat'. Then I run a command pulls the second token, the process ID from each line of the result and inserts it into the `kill` command.