mongodb 2.4.1 instance shutdown without log
It looks like the assertion you are encountering is SERVER-9053: TTL index asserts on 2.4 secondary, which was fixed in 2.4.2. This appears to be a race condition where the TTL monitor thread would incorrectly try to apply TTL deletes on a secondary. The assertion does not appear to be fatal; if it was there should be a "Fatal assertion" logged followed by the  mongod process shutting down.

Unexplained shutdowns without MongoDB log messages are commonly the result of something external to mongod, such as the Out-of-Memory (OOM) Killer on Linux. You can usually find more info on activity such as the OOM Killer by searching your system logs.

Note: MongoDB 2.4.1 was released in April, 2013 and the 2.4 release series reached end of life in March, 2016. I'd strongly recommend upgrading to the final 2.4.14 release and then planning an upgrade to a supported version.