Can't delete an edge without getting error!

[Anonymous]

I got this box I want to delete 2 edges from but it won't let me.

https://gyazo.com/a3e2cd549c63c6030ab3f4558157b8cd

When I delete them I get this error saying edges or faces may be crossing.

https://gyazo.com/cca56436b11963deb1cad4b8a3f8cdc9

And the whole car gets messed up. I don't even know why the car gets affected by me deleting some edges on a box who have nothing related with the car, it's not even on the car!

Please help and thanks in advance!

[laughingcreek]

have you tried reviewing in box mode?

You may need to attach your model to get help on this one.

[Anonymous]

I have attached the car. I have no idea why it won't let me delete the edge or even any edge without the car getting messed up. The box I made isn't even attached to the car or even close to it and when I delete an edge the car get's affected. I don't know how to fix it or even use box mode. I appreciate every help I can get, thanks in advance!