It would be better
not to add that kind of eventhandler in a script, but to do it from init field or init.sqs...
Or from the config, depending entirely on what you are doing...
But, I think the _this in the script won't matter because inside the eventhandler array the _this refers to the eventHandler, and is in it's own 'scope'...
You just need to test it
Of course that lag thing might not be so big issue as the bomb is not so fast a projectile so that EH method might not be so vital...