If the Dock fails to relaunch after killing it, is there any way to force it to relaunch?
I have finally found the answer to this question. If the Dock fails to relaunch, execute the following shell commands:
launchctl stop com.apple.Dock.agent
launchctl start com.apple.Dock.agent

The second command may not be necessary but should probably be included anyway just to be safe. This is probably a much safer way to restart the Dock than simply killing it.