Firstly, you do NOT want to install every package from NerdPack. Only install mcelog. You will run into trouble.
You're probably going to have to reboot and wait for it to happen again for any meaningful information to be generated.
Also, any particular reason you're allowing FTP access to the server from basically everywhere?
Apr 1 17:35:21 sutterstuff vsftpd[26430]: connect from 23.129.64.205 (23.129.64.205)
Apr 1 22:00:01 sutterstuff kernel: mdcmd (40): check
Apr 1 22:00:01 sutterstuff kernel: md: recovery thread: check P ...
Apr 1 23:39:27 sutterstuff vsftpd[13147]: connect from 162.142.125.55 (162.142.125.55)
Apr 1 23:41:06 sutterstuff vsftpd[13387]: connect from 71.6.232.4 (71.6.232.4)
Apr 2 00:03:05 sutterstuff vsftpd[16508]: connect from 193.169.255.246 (193.169.255.246)
Apr 2 01:41:39 sutterstuff vsftpd[30404]: connect from 65.49.20.67 (65.49.20.67)
Apr 2 02:16:05 sutterstuff kernel: mce: [Hardware Error]: Machine check events logged
Apr 2 03:40:01 sutterstuff crond[1666]: exit status 3 from user root /usr/local/sbin/mover &> /dev/null
Apr 2 06:01:09 sutterstuff vsftpd[3050]: connect from 202.102.144.121 (202.102.144.121)
Apr 2 06:50:55 sutterstuff vsftpd[10444]: connect from 185.202.2.65 (185.202.2.65)