Phantom car starter...did I just ruin my car?

I have an 07 Civic with an aftermarket remote start that was installed by the previous owner. Twice in the past month it has started itself and somehow it is connected to the alarm because the alarm goes off while the car is running. The most recent phantom start happened when I left the car at the airport. I have no idea how long the car ran but when I found her the battery was dead and about 4 gallons of gas were burned. After a jumpstart she ran fine. I am wondering what kind of damage, if any was done to my car? What should I inspect/do to make sure nothing is wrong? I am completely unfamiliar with remote starters and never use it except when it turns itself on. Any help is much appreciated.

The problem with these things, especially the aftermarket ones, stray radio signals can trigger them… The control system does not have an exclusive digital code so only your beeper can start the car…I would have a shop that installs these things remove yours before you damage the car. You may be able to disable it buy locating the power wire that feeds it and disconnecting that one wire…

Disconnect that POS.
Imagine had it started in your or someone’s garage?
The carbon monoxide could kill people in their apartments or condos.
(Idiot committed suicide in his garage. Killed two others in their condo next to his.)

Try not to be a wimp - endure a little cold for a few minutes.
Get in your cold car.
Start it.
Immediately put it in Drive.
If you can, progress toward your destination in idle - no gas.
Continue for 1 minute or until you reach a stop sign or traffic signal.
Then accelerate GENTLY.
Engine will warm faster under load, you will be using that fuel and not generating pollution needlessly, and will be that much closer to your destination than if sitting puffing.