Unable to pray on time at work?

As-salamu alaikum, I work as a security guard and most times work long hours of 10/11 and the odd one day of 6.5 hours. I am able to take one 30min break to pray my zhur. However unable to take the other 30min for magrib. Which then leaves me with no asr mag on time. Due to their rules of not allowing 15 min breaks for prayer and using my own to break it up with. What should I do? As there is no other job opportunities for me at the moment. Should I use toilet break as my prayer break? Or try to explain it would only take 5min to pray as I’m sure you can cut down to praying fard only? Thank you