At this time, while you can Start an automation for multiple contacts by clicking the "Perform Action" button and then clicking "Start Automation", you cannot cancel that automation without the following method.
Create a new automation in your "Automations" section of your account
Make your trigger "Manually Triggered"
Make your action "Cancel Automation" or "Cancel Sequence"
Activate the automation by toggling the "Active" toggle
Save your automation
Go into your "Contacts" section of your account
Click "Perform Action on Contacts"
Select the automation you just created
Finally, select the group of contacts you'd like to cancel the automation or sequence for
Complete the process. Now all of those contacts will have the automation/sequence defined in the newly created automation cancelled.
Please note, you may not "Pause" automations or sequences in this manner. Once it has been cancelled, it must be restarted from the beginning.
Now that you can cancel automations/sequences manually, you'll be able to ensure that you can handle any mistakes that may occur.