What could cause a MySQL server to "halt"?

Question

According to MySQL's help page on MEMORY engines...

When the MySQL server halts or restarts, the data in MEMORY tables is lost.

I am running a MEMORY table on an Amazon ec2 t1.micro instance, and everything was going relatively fine until about an hour ago when I realized that all of my MEMORY tables were wiped.

I did not reset the server, it is still running fine, although in my logs I realized that the CPU load was getting quite high as I was pushing the server a bit too hard it seems.

The CPU system load averages were reading 4.98, 3.32, 2.22 (1,5,15) just a few minutes before the crash.

Is it possible that the high CPU load on a single core micro instance could cause my MySQL server to "halt" and thus drop all memory tables?

Thank goodness I have a backup... I'll be restarting without pushing the server so hard this time.

I have copied my MySQL error.log file tail end below:

150511 21:14:39 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use$
150511 21:14:39 [Note] Plugin 'FEDERATED' is disabled.
150511 21:14:41 InnoDB: The InnoDB memory heap is disabled
150511 21:14:41 InnoDB: Mutexes and rw_locks use GCC atomic builtins
150511 21:14:41 InnoDB: Compressed tables use zlib 1.2.8
150511 21:14:41 InnoDB: Using Linux native AIO
150511 21:14:41 InnoDB: Initializing buffer pool, size = 128.0M
150511 21:14:42 InnoDB: Completed initialization of buffer pool
150511 21:14:42 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
150511 21:14:42  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
150511 21:14:59  InnoDB: Waiting for the background threads to start
150511 21:15:00 InnoDB: 5.5.41 started; log sequence number 12053647257
150511 21:15:00 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306
150511 21:15:00 [Note]   - '127.0.0.1' resolves to '127.0.0.1';
150511 21:15:00 [Note] Server socket created on IP: '127.0.0.1'.
150511 21:15:01 [Note] Event Scheduler: Loaded 0 events
150511 21:15:01 [Note] /usr/sbin/mysqld: ready for connections.
Version: '5.5.41-0ubuntu0.14.04.1'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  (Ubuntu)
150511 21:15:17 [ERROR] /usr/sbin/mysqld: Table './phpmyadmin/pma_column_info' is marked as crashed and should be repaired
150511 21:15:17 [Warning] Checking table:   './phpmyadmin/pma_column_info'
150511 21:15:18 [ERROR] /usr/sbin/mysqld: Table './phpmyadmin/pma_recent' is marked as crashed and should be repaired
150511 21:15:18 [Warning] Checking table:   './phpmyadmin/pma_recent'
150511 21:15:18 [ERROR] /usr/sbin/mysqld: Table './phpmyadmin/pma_table_uiprefs' is marked as crashed and should be repaired
150511 21:15:18 [Warning] Checking table:   './phpmyadmin/pma_table_uiprefs

This occurred right around when I was saying the CPU was going through the roof. I'm not sure what it all means yet, but I'm assuming the mysql server reset here. Any help would be appreciated.