It may be needed to check the database backup and restore if something goes wrong with vertica.
How to manually corrupt vertica database so that client can test if a restore is working good.
Deleting data and catalog folder would almost always mean that a full/scratch recovery would occur. If you just want to see recovery work, there are easier ways - like deleting only some of the ROS containers in data folder or even a single .gt file in a container.
You also have a high chance of corrupting data on some nodes if you manually kill a node (simulate hardware/OS crash) while there is data loading in progress.
P.S. Making suggestions how to corrupt Vertica DB is contrary to what we usually advise, so please test on a TEST/QA DB that does not contain important data and always have a full backup handy!