Quad Laser seems to be broken...or I don't know how to use it.
I've planted a couple now that charge up, don't fire, and even when I run over them again, nothing happens. It makes a sound like something happened and then charges again.
They were broken in alpha 0.4a but should've been fixed in 0.45a. Are you playing on the latest?
I'm on the latest version.
The next time it pops up, I'll try it again.