Anyone see an issue..?

[c0ncrete]

as for your timer checks, when you are using a string, you should enclose it in quotations and use the eq operator (if the name of your timer is an integer, you don't need the quotations and you use == instead). it's also better practice to use elsif for when you only expect a single condition to be met, otherwise the script will continue to evaluate the rest of the conditions instead of stopping at the first one it sees. here's an example:

Sub EVENT_TIMER
{
	if ($timer eq "DT")
	{
		quest::shout("DT timer triggered");
	}
	elsif ($timer eq "Slow")
	{
		quest::shout("Slow timer triggered");
	}
	elsif ($timer eq "Nuke")
	{
		quest::shout("Nuke timer triggered");
	}
}

additionally, i don't think it's necessary to explicitly stop timers on NPC death.