Saints Row: Gat out of Hell

This will be a lot easier in co-op, but if you fancy doing it solo, here's how I did it.

First up, open all four doors at the front of the Ultor building. If you go too far away from the doors, they will close so you're going to have to stick to the road immediately in front,

You can try to block the road a little to slow cars down. You are looking for a small white-ish car, the "Comet". Unfortunately, they seem to spawn less than all the other cars and quite often they will already be on fire when they arrive, so you will have to be patient waiting for one.

Comet's spontaneously set on fire and explode. As soon as you see one that isn't already on fire, jump in and drive as quickly as you can to the open doors.

When the car starts to set on fire, it becomes difficult to drive, so keep it as steady as possibly. Once inside, let the car explode and the achievement will pop.

Solo Method:
This method requires a little bit of patience but isn't too hard. After spawning inside the Ultor lobby, you'll want to open both sets of doors that lead inside. Once that is done, stand in front of the building and wait for cars to pass by until you see a Comet, which is a small white hatchback. Once it does, quickly hijack it! The sprinting hijack is probably recommended, and once you're inside, quickly turn into the lobby and make the car hit the main desk inside the building.

It is NOT recommended that you "Initiate Balls of Fire" once you get inside the car or else it will be significantly harder. Also, if you move too far from the doors, they will close, so do not leave the area. You can try to get in the car, drive it over, park it, open the doors and get back in, but there is a good chance that the car will get damaged and begin to explode. Once it is on fire, you will not be able to get back inside which is what makes it problematic.

Co-op Method:
Do the same method as above, but you can go ANYWHERE to find the car. Once you have it, drive it back in any condition and then have your co-op friend open the doors for you!

The Comet is a small white car that smokes. Go to the Ultor HQ and open the front doors of the building. Now look for the Comet on the street right in front of the HQ. Don't move away too far or the doors will shut. Once you get into the car you want to drive into the lobby as quick as possible, because it usually blows up pretty fast.

Easy one, Open the two door, find a comet (small white car) and drive it in.

This is a rather easy achievement. Open both doors at the Ultor building, and stand on the sidewalk out front, don't stray too far or the doors will close. Wait for a Comet (Small, white car) Hop in, and drive through the doors. If the car is not already on fire, you can crash into something. (I think you can also hold Y for it to light itself on fire.) If the achievement doesn't pop once you're in there, and on fire, try crashing and blowing up the car. Once done the achievement will pop!

First thing you want to do is find a undamaged Comet outside of the Ultor building. You can open the doors prior to finding one but if you venture too far they will close on you. The Comet is a small Fiat looking vehicle. Try not to have any notoriety if possible. Once you find the car be quick, careful, and don't hit the button that will ignite it. Just drive it through the front doors for the achievement.

Nice and easy this, the Comet tends to get stuck on the frame of the door, so get out when it does, and sprint it into the lobby, then get back in.