Two-way Arabic and Maltese conversation

I just came across this example of an Arabic speaker visiting Malta and speaking to a woman who talks to him in Maltese, and they carry out a conversation using their respective languages. You'll notice that it is a bit halting but functions well enough when done slowly, probably about the same comprehension you'd get with a French and Italian speaker slowing down the pace and speaking as clearly as possible. What I'm uncertain of (since I don't know any Arabic besides the script) is if the woman is simply toning down her Maltese, or throwing in a few Arabic words or choosing words that she knows are Arabic cognates. In other words, are they operating from a 100% L1 base or do they have a bit of an idea of which words the other knows and does not know?